/* ============================================
 *  波利亚学习助手 · 全局样式
 *  设计语言：温暖教育风格 · 简约清新 · iPad学习界面
 *  主色调：暖金色 #F59E0B | 辅色：柔和蓝灰
 * ============================================ */

/* ====== ★ 组件编号标签样式（调试用）====== */
.comp-label {
  position: absolute;
  top: -10px;
  left: -10px;
  z-index: 99999;
  background: linear-gradient(135deg, #FF6B6B, #EE5A24);
  color: #fff;
  font-size: 11px;
  font-weight: 800;
  padding: 3px 8px;
  border-radius: 20px;
  box-shadow: 0 2px 8px rgba(238,90,36,0.4), 0 1px 3px rgba(0,0,0,0.15);
  letter-spacing: 0.5px;
  font-family: 'Nunito', 'Quicksand', sans-serif;
  pointer-events: none;
  white-space: nowrap;
  line-height: 1.4;
  animation: compLabelPulse 2s ease-in-out infinite;
}
@keyframes compLabelPulse {
  0%, 100% { transform: scale(1); box-shadow: 0 2px 8px rgba(238,90,36,0.4); }
  50% { transform: scale(1.05); box-shadow: 0 4px 14px rgba(238,90,36,0.55); }
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* ============================================
 *  ★ 设计系统 Design Tokens（智慧课堂风格）
 *  基准逻辑分辨率：1366 x 1024 dp（横屏平板）
 *  栅格：12列 | 安全边距 48dp | 间距 24dp
 * ============================================ */
:root {
  /* —— 基准字号（1rem = 16px）—— */
  --base-font-size: 16px;

  /* —— 色彩体系（温暖教育风）—— */
  --bg-gradient: linear-gradient(135deg, linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%));
  --bg-gradient-subtle: linear-gradient(160deg, #FCFBF8 0%, #F3F0E9 40%, #EDE9E0 100%);
  --color-primary: #6366F1;
  --color-primary-light: #818CF8;
  --color-primary-dark: #4F46E5;
  --color-accent: #F59E0B;
  --color-accent-warm: #EA580C;
  --color-gold: #B08923;
  --color-gold-light: #F5A623;
  --color-text-primary: #1E293B;
  --color-text-secondary: #475569;
  --color-text-muted: #94A3B8;
  --color-success: #34D399;
  --color-error: #F87171;

  /* —— 圆角规范 —— */
  --radius-xl: 1.5rem;
  --radius-lg: 1rem;
  --radius-md: 0.75rem;
  --radius-sm: 0.5rem;
  --radius-full: 50rem;

  /* —— 间距体系 —— */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 3rem;
  --space-2xl: 4rem;

  /* —— 尺寸规范 —— */
  --touch-min: 3.5rem;
  --input-height: 3rem;
  --btn-height: 3rem;
  --content-max-w: 90rem;

  /* —— 玻璃拟态（温暖白）—— */
  --glass-bg: rgba(255, 255, 255, 0.72);
  --glass-bg-hover: rgba(255, 255, 255, 0.9);
  --glass-border: rgba(0, 0, 0, 0.08);
  --glass-border-subtle: rgba(0, 0, 0, 0.05);
  --glass-blur: 16px;
  --glass-shadow: 0 2px 16px rgba(0, 0, 0, 0.04), 0 1px 4px rgba(0, 0, 0, 0.03);
  --glass-shadow-hover: 0 6px 24px rgba(0, 0, 0, 0.06), 0 2px 8px rgba(0, 0, 0, 0.04);
  --glass-inset: inset 0 1px 0 rgba(255, 255, 255, 0.9);

  /* —— 导航栏 —— */
  --nav-height: 3.5rem;
  --topbar-height: 3rem;
}

/* ★ 设置 rem 基准，确保高 PPI 缩放一致性 */
html {
  font-size: var(--base-font-size);
}

body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial,
    -apple-system, BlinkMacSystemFont, 'Nunito', 'Quicksand', 'Varela Round',
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  overflow: hidden;
  overflow-x: hidden;
  width: 100vw;
  height: 100vh;
  letter-spacing: 0.3px;  /* ★ 更宽松的字母间距，儿童友好 */
  text-rendering: optimizeLegibility;     /* ★ 文本渲染优化 */
  -webkit-font-smoothing: antialiased;   /* ★ macOS/iOS 字体平滑 */
  -moz-osx-font-smoothing: grayscale;   /* ★ Firefox 字体平滑 */
}

/* ====== 页面通用样式 ====== */
.page {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: none;
  justify-content: center;
  align-items: center;
  z-index: 1;
}

.page.active {
  display: flex;
}

/* ====== ★ 柔和天蓝色渐变背景 ====== */
#page-welcome,
#page-intro,
#page-blank-1,
#page-blank-2,
#page-blank-3,
#page-blank-4,
#page-blank-5,
#page-main,
#page-practice,
#page-topic-detail,
#page-polya-guide,
#page-camera {
  background: #F8F6F0;
  position: relative;
  overflow: hidden;
}

/* ★ 浮动光点粒子（已禁用，纯色背景不需要） */
.page::before {
  display: none;
}

@keyframes floatParticles {
  0%   { transform: translate(0, 0) rotate(0deg); }
  33%  { transform: translate(15px, -10px) rotate(1deg); }
  66%  { transform: translate(-10px, 15px) rotate(-0.5deg); }
  100% { transform: translate(5px, 5px) rotate(0.5deg); }
}

/* ============================================
 *  第一页：主欢迎界面
 *  ★ 科技感升级：渐变标题 · 发光按钮 · 柔和动画
 * ============================================ */
.welcome-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 28px;           /* ★ 稍微增大间距 */
  animation: fadeInUp 1s ease-out both;
  position: relative;   /* ★ 为z-index准备 */
  z-index: 1;          /* ★ 在光点装饰之上 */
}

/* ★ Logo动画升级：更柔和的浮动 + 微光晕 */
.logo-img {
  width: 280px;
  height: auto;
  object-fit: contain;
  filter: drop-shadow(0 8px 24px rgba(91,141,239,0.2)) drop-shadow(0 4px 12px rgba(255,193,7,0.1));
  animation: floatLogoGlow 3.5s ease-in-out infinite;
}

@keyframes floatLogoGlow {
  0%, 100% { transform: translateY(0) scale(1); }
  50%      { transform: translateY(-12px) scale(1.02); }
}

/* ★ 主标题：金色渐变 + 自然柔和 */
.main-title {
  font-size: 72px;
  font-weight: 700;
  letter-spacing: 6px;
  background: linear-gradient(135deg,
    #FFD700 0%,
    #F59E0B 25%,
    #FFB300 50%,
    #F59E0B 75%,
    #FFD700 100%
  );
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  position: relative;
}

/* ★ 副标题：金色 + 描边立体 */
.sub-title {
  font-size: 30px;
  color: #F59E0B;
  letter-spacing: 10px;         /* ★ 增加字距 */
  font-weight: 600;             /* ★ 稍加粗 */
  -webkit-text-stroke: 0.8px rgba(180, 130, 0, 0.4);
  paint-order: stroke fill;
  text-shadow: 0 1px 0 rgba(160, 110, 0, 0.3);
  opacity: 0.95;
}

/* ★ 开始按钮：科技感发光效果 */
.start-btn {
  margin-top: 5rem;
  padding: 1.125rem 3.75rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: #fff;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  letter-spacing: 0.3125rem;
  min-height: var(--btn-height);
  box-shadow:
    0 6px 24px rgba(99, 102, 241, 0.35),
    0 2px 10px rgba(99, 102, 241, 0.2),
    inset 0 1px 0 rgba(255,255,255,0.2);
  transition: all 0.35s ease;
  position: relative;
  overflow: hidden;
}

/* ★ 按钮悬浮光效 */
.start-btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255,255,255,0.25),
    transparent
  );
  transition: left 0.5s ease;
}
.start-btn:hover::before {
  left: 100%;
}

.start-btn:hover {
  transform: translateY(-4px) scale(1.06);
  box-shadow:
    0 14px 40px rgba(99, 102, 241, 0.45),
    0 6px 16px rgba(99, 102, 241, 0.25),
    inset 0 1px 0 rgba(255,255,255,0.3);
}

.start-btn:active {
  transform: translateY(-1px) scale(0.98);
  box-shadow:
    0 4px 16px rgba(99, 102, 241, 0.3),
    0 2px 8px rgba(99, 102, 241, 0.15);
}

/* ============================================
 *  第二页：过渡动画界面（模糊→清晰效果）
 * ============================================ */
.intro-container {
  display: flex;
  justify-content: center;
  align-items: center;
}

.intro-text {
  font-size: 78px;
  font-weight: 700;
  color: #FFD700;             /* ★ 金色 */
  letter-spacing: 14px;
  -webkit-text-stroke: 1.5px rgba(180, 130, 0, 0.5);
  paint-order: stroke fill;
  text-shadow: 0 2px 0 rgba(160, 110, 0, 0.3);
  /* 初始状态：模糊 + 半透明 */
  opacity: 0;
  filter: blur(20px);
}

/* 模糊→清晰动画 */
.intro-text.blur-to-clear {
  animation: blurToClear 1.8s ease-out forwards;
}

/* ============================================
 *  空白预留页（P3–P7）
 *  通用样式：玻璃拟态卡片 + 上下页导航
 * ============================================ */
.blank-page-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 100%;
  max-width: var(--content-max-w);
  margin: 0 auto;
  padding: calc(var(--topbar-height) + 2rem) 3rem 2rem;
  gap: 2.5rem;
  animation: fadeInUp 0.5s ease-out both;
}

.blank-page-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.25rem;
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-xl);
  padding: 4rem 5rem;
  box-shadow: var(--glass-shadow);
}

.blank-page-icon {
  font-size: 64px;
  line-height: 1;
  filter: grayscale(0.15);
}

.blank-page-title {
  font-size: 28px;
  font-weight: 800;
  color: var(--color-text-primary);
  letter-spacing: 2px;
  -webkit-text-stroke: 0.8px rgba(30, 41, 59, 0.2);
  paint-order: stroke fill;
}

.blank-page-desc {
  font-size: 16px;
  color: var(--color-text-muted);
  letter-spacing: 1px;
}

.blank-page-nav {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.blank-nav-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: var(--input-height);
  padding: 0.75rem 2.5rem;
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.3s ease;
  min-width: 10rem;
}

.blank-prev-btn {
  color: var(--color-primary);
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}
.blank-prev-btn:hover {
  background: rgba(255,255,255,0.7);
  box-shadow: 0 4px 16px rgba(91,141,239,0.15);
  transform: translateY(-1px);
}

.blank-next-btn {
  color: #fff;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  box-shadow:
    0 4px 16px rgba(91,141,239,0.3),
    inset 0 1px 0 rgba(255,255,255,0.15);
}
.blank-next-btn:hover {
  box-shadow: 0 6px 24px rgba(91,141,239,0.4);
  transform: translateY(-2px);
}

/* ============================================
 *  第三页：主应用界面
 * ============================================ */
.top-right-logo {
  /* 定位由外层容器统一处理，这里仅设样式 */
  position: absolute;
  top: calc(var(--topbar-height) + 0.25rem) !important;
  right: 2rem !important;
  z-index: 100;
  width: 11.25rem;
  height: auto;
  object-fit: contain;
  filter: drop-shadow(0 4px 12px rgba(0, 0, 0, 0.12));
  opacity: 0.9;
  display: block;
}

/* ============================================
 *  动画定义
 * ============================================ */

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes floatLogo {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-10px);
  }
}

/* ★ 模糊→清晰过渡动画（替代原打字机效果） */
@keyframes blurToClear {
  0% {
    opacity: 0;
    filter: blur(20px);
    transform: scale(1.1);
  }
  50% {
    opacity: 0.7;
    filter: blur(8px);
    transform: scale(1.02);
  }
  100% {
    opacity: 1;
    filter: blur(0);
    transform: scale(1);
  }
}

/* ============================================
 *  调试标注系统 — 已禁用（不显示任何角标）
 * ============================================ */

/* 隐藏页码角标 */
/* ★ 全局页码角标 — 右上角悬浮 */
/* ★ 全屏按钮：科技玻璃拟态圆形 */
.fullscreen-btn {
  position: fixed;
  bottom: 1.5rem;
  right: 1.75rem;
  z-index: 999;
  width: 2.75rem;
  height: 2.75rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  line-height: 1;
  border: 1.5px solid rgba(255, 255, 255, 0.65);
  border-radius: 50%;
  background: linear-gradient(
    135deg,
    rgba(255, 255, 255, 0.65) 0%,
    rgba(255, 255, 255, 0.45) 100%
  );
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  color: var(--color-accent);
  cursor: pointer;
  transition: all 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  box-shadow:
    0 6px 24px rgba(99, 102, 241, 0.12),
    0 2px 8px rgba(0,0,0,0.04),
    inset 0 1px 0 rgba(255,255,255,0.6);
}
.fullscreen-btn:hover {
  background: linear-gradient(
    135deg,
    rgba(255, 255, 255, 0.85) 0%,
    rgba(255, 255, 255, 0.65) 100%
  );
  border-color: rgba(99, 102, 241, 0.4);
  box-shadow:
    0 10px 36px rgba(99, 102, 241, 0.18),
    0 3px 14px rgba(99, 102, 241, 0.1),
    inset 0 1px 0 rgba(255,255,255,0.85);
  transform: translateY(-4px) scale(1.1);
}
.fullscreen-btn:active {
  transform: translateY(0) scale(0.95);
}

.polya-avatar {
  width: 18.75rem;
  height: auto;
  object-fit: contain;
  filter: drop-shadow(0 4px 16px rgba(0, 0, 0, 0.15));
  position: absolute;
  bottom: 1.5rem !important;
  left: 1.25rem !important;
}

/* ============================================
 *  波利亚介绍问号按钮 + 气泡 + 浮动弹窗（P3右下角）
 * ============================================ */

/* ★ 问号按钮：科技玻璃拟态胶囊形 */
.polya-info-btn {
  position: fixed;
  bottom: 4.5rem;
  right: 1.75rem;
  z-index: 150;
  display: inline-flex;
  align-items: center;
  gap: 10px;                 /* ★ 增大间距 */
  padding: 12px 20px 12px 14px;   /* ★ 稍大内边距 */
  height: auto;
  border-radius: 32px;        /* ★ 更圆润 */
  border: 1.5px solid rgba(255, 255, 255, 0.65);
  background: linear-gradient(
    135deg,
    rgba(255, 255, 255, 0.65) 0%,
    rgba(255, 255, 255, 0.45) 100%
  );
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  color: #FFD700;            /* ★ 金色 */
  font-size: 13.5px;         /* ★ 稍大 */
  font-weight: 700;          /* ★ 加粗 */
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);   /* ★ 更流畅动画 */
  line-height: 1.4;
  white-space: nowrap;
  box-shadow:
    0 6px 24px rgba(99, 102, 241, 0.12),
    0 2px 8px rgba(0,0,0,0.04),
    inset 0 1px 0 rgba(255,255,255,0.6);
}

.polya-info-btn:hover {
  background: linear-gradient(
    135deg,
    rgba(255, 255, 255, 0.85) 0%,
    rgba(255, 255, 255, 0.65) 100%
  );
  border-color: rgba(99, 102, 241, 0.4);
  box-shadow:
    0 10px 36px rgba(99, 102, 241, 0.18),
    0 3px 14px rgba(99, 102, 241, 0.1),
    inset 0 1px 0 rgba(255,255,255,0.85);
  transform: translateY(-4px) scale(1.05);   /* ★ 更明显上浮 */
}

/* ====== 右下角浮动弹窗（替代原居中弹窗）====== */
.polya-popover {
  position: fixed;
  bottom: 7.5rem;
  right: 1.75rem;
  width: 340px;
  z-index: 9999;
  display: none;
  flex-direction: column;
  animation: popoverSlideUp 0.3s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}
.polya-popover.show { display: flex; }

@keyframes popoverSlideUp {
  from { opacity: 0; transform: translateY(16px) scale(0.94); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}

@keyframes popoverFadeOut {
  from { opacity: 1; transform: translateY(0) scale(1); }
  to   { opacity: 0; transform: translateY(16px) scale(0.94); }
}

/* 弹窗主体 — 玻璃拟态（浅色清新风） */
.polya-popover {
  background: rgba(255, 255, 255, 0.75);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1.5px solid rgba(99, 102, 241, 0.2);    /* ★ 主色淡边框 */
  border-radius: 18px;
  padding: 20px 18px 16px;
  box-shadow:
    0 8px 32px rgba(99, 102, 241, 0.1),
    0 2px 8px rgba(0, 0, 0, 0.04);
}

/* 标题 */
.polya-popover-title {
  font-size: 17px;
  color: #DAA520;           /* ★ 金色 */
  text-align: center;
  margin-bottom: 14px;
  letter-spacing: 1.5px;
  padding-right: 20px;
}

/* 内容区 */
.polya-popover-body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.polya-popover-img {
  width: 130px;
  height: auto;
  object-fit: contain;
  border-radius: 12px;
  border: 1.5px solid rgba(99, 102, 241, 0.2);   /* ★ 主色 */
  filter: drop-shadow(0 3px 10px rgba(0,0,0,0.1));
}

.polya-popover-text {
  font-size: 15px;
  line-height: 1.75;
  color: #222;               /* ★ 黑色 */
  text-align: justify;
}
.polya-popover-text p {
  text-indent: 2em;
  margin: 0;
}
.polya-popover-text p + p {
  margin-top: 10px;
}

/* 底部小三角箭头 */
.polya-popover-arrow {
  width: 0;
  height: 0;
  margin: 0 auto;
  border-left: 10px solid transparent;
  border-right: 10px solid transparent;
  border-top: 10px solid rgba(255, 255, 255, 0.75);
}

/* ============================================
 *  第三页：P3 主功能区（菜单卡片）
 *  ★ 科技感升级：增强玻璃拟态 · 圆润化 · 光晕边框
 * ============================================ */

.main-menu {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2.25rem;
  padding: 3.125rem 2.5rem 7.5rem;
  max-width: var(--content-max-w);
  margin: 0 auto;
  width: 100%;
}

/* --- ★ 第一行：两个主功能大卡片 --- */
.menu-top-row {
  display: flex;
  justify-content: center;
  gap: 30px;              /* ★ 增大间距 */
}

/* ★ 高亮行容器 */
.menu-highlight-row {
  gap: 1.625rem;
  padding: 0.625rem;
  border-radius: var(--radius-xl);
  background: rgba(255,255,255,0.25);
  box-shadow:
    inset 0 1px 2px rgba(255,255,255,0.5),
    0 4px 20px rgba(91,141,239,0.06);
}

/* ★ 功能卡片：科技玻璃拟态（增强可见度） */
.menu-feature-card {
  background: var(--glass-bg) !important;
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border) !important;
  border-radius: var(--radius-lg) !important;
  position: relative;
  overflow: hidden;
  box-shadow: var(--glass-shadow), var(--glass-inset) !important;
}
/* ★ 卡片顶部高光（增强） */
.menu-feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 50%;
  background: linear-gradient(
    to bottom,
    rgba(255,255,255,0.25),
    transparent
  );
  pointer-events: none;
}
.menu-feature-card > .card-title,
.menu-feature-card .card-title {
  color: #DAA520 !important;            /* ★ 金色 */
  font-weight: 800;                /* ★ 加粗 */
  letter-spacing: 0.5px;
}
.menu-feature-card > .card-desc,
.menu-feature-card .card-desc {
  color: #333 !important;    /* ★ 黑色 */
  line-height: 1.6;
}
/* ★ Hover：发光效果 */
.menu-feature-card:hover {
  background: var(--glass-bg-hover) !important;
  border-color: rgba(99, 102, 241, 0.35) !important;
  transform: translateY(-8px) scale(1.03);
  box-shadow: var(--glass-shadow-hover), var(--glass-inset) !important;
}

/* --- 功能卡片通用样式（科技玻璃拟态·增强可见度）--- */
.menu-card {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-lg);
  padding: 2.375rem 2.5rem;
  width: 19.375rem;
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  position: relative;
  overflow: hidden;
  box-shadow: var(--glass-shadow), var(--glass-inset);
}

/* ★ 通用卡片顶部高光（增强） */
.menu-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 50%;
  background: linear-gradient(
    to bottom,
    rgba(255,255,255,0.22),
    transparent
  );
  pointer-events: none;
}

.menu-card:hover {
  transform: translateY(-8px) scale(1.03);
  background: var(--glass-bg-hover);
  box-shadow: var(--glass-shadow-hover);
  border-color: rgba(99, 102, 241, 0.3);
}

/* ★ 波利亚介绍卡片：hover 更低调 */
.card-wide:hover {
  transform: translateY(-3px);
  background: rgba(255, 255, 255, 0.13);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.1);
}

.menu-card:active {
  transform: translateY(-2px) scale(1.0);
}

.card-icon {
  font-size: 48px;           /* 原42 → 48，配合大卡片 */
  margin-bottom: 12px;
}

.card-title {
  font-size: 24px;
  font-weight: 700;
  color: #DAA520;            /* ★ 金色（深金） */
  margin-bottom: 6px;
}

.card-desc {
  font-size: 14px;
  color: #333;               /* ★ 黑色 */
  line-height: 1.5;
}

.card-arrow {
  position: absolute;
  right: 20px;
  bottom: 18px;
  font-size: 22px;
  color: #DAA520;            /* ★ 金色 */
}

/* --- ★ 波利亚四步法：全宽介绍卡片（次要功能）— 玻璃拟态 --- */
.card-wide {
  width: 100%;
  max-width: 56.25rem;
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  padding: 1.5rem 2rem;
  box-shadow: var(--glass-shadow);
}

.method-header {
  display: flex;
  flex-direction: column;       /* 改为纵向，容纳标题行+功能按钮行 */
  gap: 16px;
  margin-bottom: 20px;
}

/* --- 四步法步骤区域 --- */
.method-steps {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

.step-card {
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-md);
  padding: 1rem 1.125rem;
  cursor: pointer;
  transition: all 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  display: flex;
  gap: 0.75rem;
  align-items: flex-start;
}

.step-card:hover {
  background: rgba(255, 255, 255, 0.8);
  border-color: rgba(255, 193, 7, 0.4);   /* ★ 辅色 */
  transform: translateY(-4px) scale(1.02);
  box-shadow: 0 6px 20px rgba(255, 193, 7, 0.12), 0 2px 8px rgba(0, 0, 0, 0.06), 0 0 20px rgba(255, 193, 7, 0.04);
}

.step-num {
  font-size: 26px;
  font-weight: 800;
  color: #DAA520;            /* ★ 金色（浅底上更醒目） */
  min-width: 32px;
  text-align: center;
  line-height: 1;
  margin-top: 2px;
}

.step-info h4 {
  font-size: 17px;
  font-weight: 600;
  color: #222;               /* ★ 黑色 */
  margin-bottom: 6px;
}

.step-detail {
  font-size: 13px;
  color: #444;               /* ★ 黑色（稍浅） */
  line-height: 1.65;
  transition: all 0.35s ease;
  margin-top: 6px;
}

.step-detail.hidden {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  margin: 0;
  padding: 0;
}

.step-detail.visible {
  max-height: 200px;
  opacity: 1;
  margin-top: 6px;
}

/* ============================================
 *  第四页：P4 题目练习界面
 *  ★ 科技感升级：圆润卡片 · 柔和光晕
 * ============================================ */

/* --- 可滚动容器 --- */
.practice-container {
  width: 100%;
  max-width: var(--content-max-w);
  margin: 0 auto;
  padding: calc(var(--topbar-height) + 1.5rem) 3rem 2rem;
  overflow-y: auto;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  box-sizing: border-box;
  scroll-behavior: smooth;
  position: relative;
  z-index: 1;
  /* 隐藏滚动条 */
  scrollbar-width: none;
  -ms-overflow-style: none;
}

/* Chrome/Safari 隐藏滚动条 */
.practice-container::-webkit-scrollbar { display: none; }

/* --- 返回按钮：科技玻璃拟态 --- */
.back-btn {
  position: fixed;
  top: calc(var(--topbar-height) + 0.75rem);
  left: 2rem;
  z-index: 200;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.75rem;
  min-height: var(--touch-min);
  min-width: var(--touch-min);
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--color-gold);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.35s ease;
  letter-spacing: 0.125rem;
  box-shadow: var(--glass-shadow);
}

.back-btn:hover {
  background: linear-gradient(
    135deg,
    rgba(255, 255, 255, 0.9) 0%,
    rgba(255, 255, 255, 0.65) 100%
  );
  border-color: rgba(99, 102, 241, 0.4);
  transform: translateX(6px) translateY(-2px);
  box-shadow:
    0 6px 20px rgba(99, 102, 241, 0.15),
    0 2px 8px rgba(0, 0, 0, 0.06);
}

/* --- 页面标题区：渐变文字 + 描边立体 --- */
.practice-header {
  text-align: center;
  margin-bottom: 24px;
}

.page-title {
  font-size: 38px;
  font-weight: 800;
  background: linear-gradient(135deg, #FFD700, #F59E0B, #FFB300);   /* ★ 金色渐变 */
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  -webkit-text-stroke: 1px rgba(180, 130, 0, 0.45);
  paint-order: stroke fill;
  letter-spacing: 2px;
  margin-bottom: 8px;
  text-align: center;
  filter: none;
}

.page-subtitle {
  font-size: 17px;
  color: #444;               /* ★ 黑色（稍浅） */
  text-align: center;
  margin-bottom: 20px;
  letter-spacing: 1px;
  opacity: 0.9;
}

/* --- 专题切换器样式 --- */
.topic-switcher {
  display: flex;
  justify-content: center;
  margin-bottom: 12px;
}

.topic-select {
  appearance: none;
  -webkit-appearance: none;
  padding: 12px 48px 12px 20px;
  font-size: 16px;
  font-weight: 600;
  color: #fff;
  background: linear-gradient(135deg, #6366F1, #4F46E5);
  border: none;
  border-radius: 24px;
  cursor: pointer;
  outline: none;
  box-shadow: 0 4px 16px rgba(99, 102, 241, 0.3), 0 2px 6px rgba(0, 0, 0, 0.1);
  transition: all 0.3s ease;
  letter-spacing: 1px;
  min-width: 280px;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23fff' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 16px center;
}

.topic-select:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(99, 102, 241, 0.45), 0 3px 10px rgba(0, 0, 0, 0.12);
}

.topic-select:active {
  transform: translateY(0);
}

.topic-select option {
  padding: 10px;
  background: #fff;
  color: #333;
  font-weight: 500;
}

/* --- P4：知识点专题网格列表 --- */
.topic-list {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;               /* ★ 增大间距 */
  padding: 10px 0;
}

/* --- 单个专题卡片：科技玻璃拟态（增强可见度）--- */
.topic-card {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.375rem 1.125rem;
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 0.5rem;
  user-select: none;
  position: relative;
  overflow: hidden;
  box-shadow: var(--glass-shadow), var(--glass-inset);
}

/* ★ 卡片顶部高光（增强） */
.topic-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 50%;
  background: linear-gradient(to bottom, rgba(255,255,fff,0.22), transparent);
  pointer-events: none;
}

.topic-card:hover {
  border-color: rgba(255, 193, 7, 0.45);
  background: linear-gradient(
    135deg,
    rgba(255, 255, 255, 0.75) 0%,
    rgba(255, 255, 255, 0.5) 100%
  );
  box-shadow:
    0 10px 32px rgba(255, 193, 7, 0.12),
    0 2px 10px rgba(0, 0, 0, 0.06),
    0 0 28px rgba(255, 193, 7, 0.05),
    inset 0 1px 0 rgba(255,255,255,0.8);
  transform: translateY(-6px) scale(1.03);   /* ★ 更明显上浮 */
}

.topic-card:active {
  transform: translateY(-2px) scale(0.98);
}

/* ====== ★ P4知识点卡片：星级 ====== */
.topic-stars-row {
  display: flex;
  gap: 5px;
  font-size: 22px;
  line-height: 1;
  justify-content: center;
}
.topic-star {
  color: rgba(255,255,255,0.18);
  transition: all 0.35s ease;
}
.topic-star.lit {
  color: #F59E0B;
  text-shadow: 0 0 14px rgba(255, 193, 7, 0.65), 0 0 4px rgba(255, 160, 0, 0.8);  /* ★ 增强发光 */
}

/* --- P4 卡片内部元素 --- */
.topic-icon {
  font-size: 40px;           /* ★ 稍大 */
  line-height: 1;
  filter: drop-shadow(0 2px 6px rgba(0,0,0,0.08));
}

.topic-name {
  font-size: 17px;
  font-weight: 800;           /* ★ 加粗 */
  color: #222;               /* ★ 黑色 */
  line-height: 1.4;
  letter-spacing: 0.3px;
}

.topic-count {
  font-size: 12px;
  color: #DAA520;            /* ★ 金色 */
  font-weight: 600;
}

/* --- 单道题目卡片：科技玻璃拟态 --- */
.problem-item {
  background: var(--glass-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.375rem;
  margin-bottom: 0.875rem;
  transition: all 0.3s ease;
  box-shadow: var(--glass-shadow);
}

.problem-item:last-child {
  margin-bottom: 0;
}

.problem-item:hover {
  background: rgba(255, 255, 255, 0.6);
  border-color: rgba(255, 193, 7, 0.3);   /* ★ 辅色 */
}

.problem-index {
  display: inline-block;
  width: 28px;
  height: 28px;
  line-height: 28px;
  text-align: center;
  background: linear-gradient(135deg, #6366F1, #4F46E5);   /* ★ 主色渐变 */
  color: #fff;                                        /* 白字 */
  font-size: 13px;
  font-weight: 800;
  border-radius: 50%;
  margin-right: 10px;
  vertical-align: middle;
  box-shadow: 0 2px 8px rgba(99, 102, 241, 0.25);
}

.problem-question {
  display: inline;
  font-size: 16px;
  color: #1a1a1a;            /* ★ 黑色 */
  line-height: 1.7;
  vertical-align: middle;
}

/* 题目内的公式容器 — MathJax渲染后使用 */
.problem-question mjx-container {
  margin: 0 2px;
}

/* --- 解析答案区域 --- */
.problem-answer {
  margin-top: 14px;
  padding: 14px 18px;
  background: rgba(227, 242, 253, 0.8);      /* ★ 浅蓝背景 */
  border-left: 3px solid #6366F1;             /* ★ 主色左边框 */
  border-radius: 0 10px 10px 0;
}

.answer-label {
  font-size: 13px;
  font-weight: 700;
  color: #B8860B;            /* ★ 金色深变体 */
  margin-bottom: 6px;
  letter-spacing: 2px;
}

.answer-text {
  font-size: 15px;
  color: #1a1a1a;            /* ★ 黑色 */
  line-height: 1.8;
}

/* --- 教学建议区域 --- */
.problem-suggestion {
  margin-top: 10px;
  padding: 10px 16px;
  background: rgba(255, 248, 225, 0.8);       /* ★ 极淡黄背景 */
  border: 1px dashed rgba(255, 193, 7, 0.3);
  border-radius: 10px;
}

.suggestion-label {
  font-size: 12px;
  font-weight: 600;
  color: #F57C00;           /* ★ 橙色 */
  margin-bottom: 4px;
}

.suggestion-text {
  font-size: 14px;
  color: #444;               /* ★ 黑色（稍浅） */
  line-height: 1.65;
}

/* ============================================
  *  第五页：P5 知识点详情界面
  * ============================================ */

#page-topic-detail {
  background: #F8F6F0;
}

.topic-detail-container {
  width: 100%;
  max-width: var(--content-max-w);
  margin: 0 auto;
  padding: calc(var(--topbar-height) + 1.5rem) 3rem 2rem;
  height: 100vh;
  overflow-y: auto;
  box-sizing: border-box;
  scroll-behavior: smooth;
  /* 隐藏滚动条 */
  scrollbar-width: none;
  -ms-overflow-style: none;
}

/* 隐藏滚动条（Chrome/Safari） */
.topic-detail-container::-webkit-scrollbar {
  display: none;
}

/* --- P5 页面标题 --- */
.topic-detail-title {
  font-size: 30px;
  font-weight: 800;
  color: #DAA520;            /* ★ 金色 */
  text-align: center;
  margin-bottom: 28px;
  -webkit-text-stroke: 0.8px rgba(140, 100, 0, 0.35);
  paint-order: stroke fill;
  text-shadow: 0 1px 0 rgba(120, 80, 0, 0.25);
}

/* ====== ★ 知识点进度与星级评价卡片 — 玻璃拟态 ====== */
.topic-progress-card {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.125rem 1.5rem;
  margin-bottom: 1.25rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.625rem;
  animation: fadeInUp 0.45s ease both;
}

/* 星级行 */
.tp-stars-row {
  display: flex;
  gap: 8px;
  font-size: 32px;
  line-height: 1;
}
.tp-star {
  color: rgba(255,255,255,0.2);
  transition: all 0.35s ease;
  filter: drop-shadow(0 2px 4px rgba(0,0,0,0.15));
  cursor: default;
}
/* 激活（点亮）的星 */
.tp-star.lit {
  color: #F59E0B;           /* ★ 辅色琥珀黄 */
  text-shadow: 0 0 16px rgba(255, 193, 7, 0.6), 0 0 4px rgba(255, 160, 0, 0.8);
  animation: starPopIn 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}
@keyframes starPopIn {
  0%   { transform: scale(0.3) rotate(-15deg); opacity: 0; }
  60%  { transform: scale(1.25) rotate(5deg); }
  100% { transform: scale(1) rotate(0deg); opacity: 1; }
}

/* 进度文字 */
.tp-progress-text {
  font-size: 13px;
  font-weight: 600;
  color: #333;               /* ★ 黑色 */
  letter-spacing: 1px;
}

/* 进度条外框 */
.tp-progress-bar-outer {
  width: 100%;
  max-width: 360px;
  height: 8px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 4px;
  overflow: hidden;
}
/* 进度条内填充 */
.tp-progress-bar-inner {
  height: 100%;
  background: linear-gradient(90deg, #6366F1, #29B6F6, #F59E0B);   /* ★ 主色→浅主色→辅色 */
  border-radius: 4px;
  transition: width 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* ====== ★ 清空记录按钮（右下角悬浮）— 玻璃拟态 ====== */
.clear-record-btn {
  position: fixed;
  bottom: 4.5rem;
  right: 1.75rem;
  z-index: 500;
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 10px 18px;
  background: rgba(255, 255, 255, 0.6);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1.5px solid rgba(99, 102, 241, 0.2);     /* ★ 主色淡边框 */
  border-radius: 14px;
  color: #333;               /* ★ 黑色 */
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 3px 14px rgba(99, 102, 241, 0.08), 0 1px 4px rgba(0,0,0,0.03);
  letter-spacing: 1px;
}
.clear-record-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 22px rgba(200, 70, 70, 0.2), 0 2px 8px rgba(0,0,0,0.06);
  background: linear-gradient(135deg, rgba(239,83,80,0.7), rgba(211,47,47,0.6));
  border-color: rgba(239,83,80,0.35);
  color: #fff;
}
.clear-record-btn:active { transform: translateY(0); }

/* --- 题目列表区域 --- */
.question-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

/* --- 单道题目条目（仅题目，可点击展开答题） --- */
/* 进入单题模式后，非激活的题目自动隐藏 */
#question-list.quiz-single-mode .question-item:not(.active) {
  display: none;
}
#question-list.quiz-single-mode .question-item.active {
  display: block !important;
}

.question-item {
  background: var(--glass-bg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem;
  cursor: pointer;
  transition: all 0.35s ease;
  user-select: none;
  box-shadow: var(--glass-shadow);
}

.question-item:hover {
  border-color: rgba(255, 193, 7, 0.35);      /* ★ 辅色 */
  background: rgba(255, 255, 255, 0.6);
  transform: translateX(6px);
}

.question-item.answered {
  border-color: rgba(76, 175, 80, 0.5);
}

/* ====== ★ 题目状态样式（高饱和度 + 印章式标签）====== */

/* 状态1：答错 — 红色 */
.question-item.q-status-wrong {
  border-color: rgba(229, 57, 53, 0.95) !important;
  background: rgba(211, 47, 47, 0.22) !important;
  box-shadow: 0 0 18px rgba(229, 57, 53, 0.2), inset 0 0 20px rgba(229, 57, 53, 0.06);
}

/* 状态2：答对跳过解析 — 绿色 */
.question-item.q-status-correct-skip {
  border-color: rgba(76, 175, 80, 0.9) !important;
  background: rgba(46, 125, 50, 0.2) !important;
  box-shadow: 0 0 18px rgba(76, 175, 80, 0.18), inset 0 0 20px rgba(46, 125, 50, 0.06);
}

/* 状态3：答错后掌握 — 翠绿（入错题本）*/
.question-item.q-status-wrong-mastered {
  border-color: rgba(56, 239, 125, 0.95) !important;
  background: rgba(46, 180, 110, 0.2) !important;
  box-shadow: 0 0 20px rgba(56, 239, 125, 0.2), inset 0 0 20px rgba(56, 239, 125, 0.06);
}

/* 状态4：完美掌握 — 辅色琥珀黄 */
.question-item.q-status-perfect {
  border-color: rgba(255, 193, 7, 1) !important;
  background: linear-gradient(135deg, rgba(255, 193, 7, 0.25), rgba(255, 152, 0, 0.2)) !important;
  box-shadow: 0 0 28px rgba(255, 193, 7, 0.3), inset 0 0 24px rgba(255, 193, 7, 0.08);
}

/* ★ 状态标签 — 印章风格（醒目、粗体、带旋转变换）*/
.q-status-tag {
  display: inline-block;
  font-size: 14px;
  padding: 4px 14px;
  border-radius: 6px;
  margin-left: 10px;
  vertical-align: middle;
  white-space: nowrap;
  opacity: 1 !important;
  font-weight: 800;
  letter-spacing: 2px;
  transform: rotate(-3deg);
  box-shadow: 0 2px 8px rgba(0,0,0,0.25);
  text-shadow: 0 1px 2px rgba(0,0,0,0.3);
}
.q-tag-wrong {
  color: #fff;
  background: rgba(211, 47, 47, 0.88) !important;
  border: 2px solid rgba(244, 67, 54, 0.95) !important;
  transform: rotate(-5deg) scale(1.05);
}
.q-tag-green {
  color: #fff;
  background: rgba(46, 125, 50, 0.85) !important;
  border: 2px solid rgba(76, 175, 80, 0.9) !important;
  transform: rotate(-2deg);
}
.q-tag-gold {
  color: #1b5e20;
  background: linear-gradient(135deg, #69f0ae, #00e676) !important;
  border: 2px solid rgba(56, 239, 125, 0.95) !important;
  transform: rotate(-4deg) scale(1.05);
  text-shadow: 0 1px 0 rgba(255,255,255,0.4);
}

.question-index-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 26px;
  height: 26px;
  padding: 0 8px;
  background: linear-gradient(135deg, #6366F1, #4F46E5);   /* ★ 主色渐变 */
  color: #fff;                                          /* 白字 */
  font-size: 13px;
  font-weight: 800;
  border-radius: 8px;
  margin-right: 12px;
  vertical-align: middle;
  box-shadow: 0 2px 8px rgba(99, 102, 241, 0.25);
}

.question-text {
  display: inline;
  font-size: 16px;
  color: #1a1a1a;            /* ★ 黑色 */
  line-height: 1.7;
  vertical-align: middle;
}

/* mjx-container 内边距 */
.question-text mjx-container,
.answer-text mjx-container {
  margin: 0 2px;
}

.question-main-row {
  display: flex;
  align-items: flex-start;
  gap: 10px;
}

.question-main-row .question-text {
  flex: 1;
}

.question-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px dashed rgba(99, 102, 241, 0.18);
}

.question-actions button {
  min-height: 38px;
  padding: 9px 15px;
  border: none;
  border-radius: 10px;
  color: #fff;
  font-size: 13px;
  font-weight: 800;
  cursor: pointer;
  transition: all 0.25s ease;
  box-shadow: 0 3px 10px rgba(99, 102, 241, 0.18);
}

.question-actions button:hover {
  transform: translateY(-2px);
}

.qc-start-btn {
  background: linear-gradient(135deg, #6366F1, #4F46E5);
}

.qc-toggle-btn {
  background: linear-gradient(135deg, #FFB340, #FF9F1C);
}

.qc-mistake-btn {
  background: linear-gradient(135deg, #F87171, #DC2626);
}

/* --- 答题区域（点击题目后展开） --- */
.answer-area {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.45s ease, padding 0.35s ease;
  padding: 0 20px;
}

.question-item.expanded .answer-area {
  max-height: 1200px;
  padding: 20px 20px 8px;
}

.answer-prompt {
  font-size: 15px;
  font-weight: 600;
  color: #DAA520;            /* ★ 金色 */
  margin-bottom: 4px;
  letter-spacing: 2px;
  text-align: center;
}

/* --- 答案格式提示 --- */
.answer-hint {
  font-size: 12px;
  color: #666;               /* ★ 深灰黑 */
  text-align: center;
  margin-bottom: 10px;
  font-style: italic;
}

/* ==================== 选择题选项样式 ==================== */
.choices-container {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 14px;
}

.choice-option {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  padding: 0.75rem 0.875rem;
  min-height: var(--touch-min);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.25s ease;
  background: rgba(255, 255, 255, 0.4);
  border: 1.5px solid rgba(99, 102, 241, 0.15);
  user-select: none;
}

.choice-option:hover {
  background: rgba(99, 102, 241, 0.08);
  border-color: rgba(99, 102, 241, 0.35);
  transform: translateX(4px);
}

.choice-option input[type="radio"] {
  appearance: none;
  -webkit-appearance: none;
  width: 22px;
  height: 22px;
  min-width: 22px;
  border: 2.5px solid rgba(99, 102, 241, 0.4);
  border-radius: 50%;
  cursor: pointer;
  transition: all 0.2s ease;
  position: relative;
  background: #fff;
}

.choice-option input[type="radio"]:checked {
  border-color: #6366F1;           /* ★ 主色 */
  background: transparent;
}

.choice-option input[type="radio"]:checked::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #6366F1;           /* ★ 主色 */
  box-shadow: 0 0 8px rgba(99, 102, 241, 0.35);
}

.choice-option input[type="radio"]:disabled {
  cursor: default;
}

/* 选项标签 A B C D */
.choice-label {
  font-size: 17px;
  font-weight: 800;
  color: #DAA520;            /* ★ 金色 */
  min-width: 26px;
  text-align: center;
  letter-spacing: 1px;
}

/* 选项文本 */
.choice-text {
  font-size: 15px;
  color: #222;               /* ★ 黑色 */
  line-height: 1.5;
  word-break: break-word;
}

/* ===== 提交后状态高亮 ===== */

/* 正确答案 - 绿色边框 + 背景 */
.choice-option.choice-correct {
  background: rgba(76, 217, 100, 0.15);
  border-color: rgba(76, 217, 100, 0.6);
  box-shadow: 0 0 16px rgba(76, 217, 100, 0.15);
}

.choice-option.choice-correct .choice-label {
  color: #4cd964;
}

/* 用户选错 - 红色边框 + 背景 */
.choice-option.choice-wrong {
  background: rgba(255, 69, 58, 0.15);
  border-color: rgba(255, 69, 58, 0.6);
  box-shadow: 0 0 16px rgba(255, 69, 58, 0.15);
  animation: shakeX 0.4s ease;
}

.choice-option.choice-wrong .choice-label {
  color: #ff453a;
}

/* 用户选中（正确时也显示） */
.choice-option.choice-selected {
  background: rgba(255, 215, 0, 0.08);
}

@keyframes shakeX {
  0%, 100% { transform: translateX(0); }
  20% { transform: translateX(-6px); }
  40% { transform: translateX(6px); }
  60% { transform: translateX(-4px); }
  80% { transform: translateX(4px); }
}

.answer-input-wrapper {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 14px;
}

.user-answer-input {
  flex: 1;
  padding: 0.75rem 1.125rem;
  font-size: 1rem;
  min-height: var(--input-height);
  background: rgba(255, 255, 255, 0.85);
  border: 2px solid rgba(99, 102, 241, 0.25);
  border-radius: var(--radius-sm);
  outline: none;
  color: #333;
  transition: all 0.3s ease;
}

.user-answer-input:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

.submit-answer-btn {
  padding: 0.75rem 1.75rem;
  font-size: 0.9375rem;
  font-weight: 700;
  min-height: var(--btn-height);
  color: #fff;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.3s ease;
  white-space: nowrap;
  box-shadow: 0 3px 12px rgba(99, 102, 241, 0.25), 0 1px 4px rgba(99, 102, 241, 0.1);
}

.submit-answer-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.35), 0 2px 8px rgba(99, 102, 241, 0.15);
}

.submit-answer-btn:active {
  transform: translateY(0);
}

/* --- 答案结果反馈区 --- */
.answer-result {
  padding: 16px 20px;
  border-radius: 12px;
  margin-top: 10px;
  animation: fadeInUp 0.4s ease both;
}

.answer-result.correct {
  background: rgba(76, 175, 80, 0.15);
  border-left: 4px solid #4caf50;
}

.answer-result.wrong {
  background: rgba(244, 67, 54, 0.15);
  border-left: 4px solid #f44336;
}

.result-label {
  font-size: 14px;
  font-weight: 700;
  margin-bottom: 8px;
}

.answer-result.correct .result-label { color: #81c784; }
.answer-result.wrong .result-label { color: #e57373; }

.result-text {
  font-size: 14px;
  color: #1a1a1a;            /* ★ 黑色 */
  line-height: 1.75;
}

/* --- 正确答案解析展示 --- */
.correct-answer-box {
  margin-top: 12px;
  padding: 14px 18px;
  background: rgba(102, 126, 234, 0.12);
  border: 1px solid rgba(102, 126, 234, 0.25);
  border-radius: 10px;
}

.correct-answer-title {
  font-size: 13px;
  font-weight: 700;
  color: #B8860B;            /* ★ 金色深变体 */
  margin-bottom: 8px;
  letter-spacing: 1px;
}

.correct-answer-body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
  font-size: 14px;
  color: #1a1a1a;            /* ★ 黑色 */
  line-height: 1.8;
}

/* ============================================
   ★ 波利亚四步法页面 [P6] - 左右分栏布局
   左侧：题目 + 进度条（窄）
   右侧：对话 + 输入区（宽）
   ============================================ */

#page-polya-guide {
  background: #F8F6F0;
}

/* ============================================
   ★ 波利亚四步法页面 [P6] - 纵向单栏布局
   题目 → 四步进度条 → 对话框(全宽) → 输入区
   ============================================ */
.polya-guide-container {
  width: 100%;
  height: 100vh;
  padding: calc(var(--topbar-height) + 1.5rem) 1.5rem 2rem;
  padding-left: 17.5rem;
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  max-width: var(--content-max-w);
  margin: 0 auto;
  overflow-x: hidden;
  overflow-y: auto;
  scrollbar-width: thin;
}
.polya-guide-container::-webkit-scrollbar { width: 5px; }
.polya-guide-container::-webkit-scrollbar-track { background: transparent; }
.polya-guide-container::-webkit-scrollbar-thumb { background: rgba(255,193,7,0.3); border-radius: 4px; }

/* ★ 左右两栏布局已废弃，隐藏相关样式 */
.pg-left-column,
.pg-right-column { display: none !important; }

/* ============================================
   ★ 波利亚四步法页面 [P6] - 科技感升级
   布局：题目窗口 → 四步进度条 → 对话区 → 输入区
   ============================================ */

/* --- 独立题目展示窗口：科技玻璃拟态 --- */
.pg-problem-window {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-xl);
  padding: 0.875rem 1.625rem;
  max-width: none;
  width: 100%;
  margin-left: auto;
  margin-right: auto;
  flex-shrink: 0;
  position: relative;
  overflow: hidden;
  box-shadow: var(--glass-shadow), var(--glass-inset);
}

/* ★ 题目窗口顶部高光 */
.pg-problem-window::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 50%;
  background: linear-gradient(to bottom, rgba(255,255,255,0.15), transparent);
  pointer-events: none;
}

.pg-problem-window-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}

.pg-problem-icon {
  font-size: 22px;
}

.pg-problem-label {
  font-size: 15px;
  font-weight: 800;
  color: #DAA520;           /* ★ 金色 */
  letter-spacing: 4px;
  text-transform: uppercase;
}

.pg-problem-window-body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
  font-size: 17px;
  color: #1a1a2e;
  line-height: 1.85;
  min-height: 32px;
  font-weight: 500;
  text-shadow: 0 1px 2px rgba(255,255,255,0.5);
}

/* --- ★ 波利亚四步进度条（全宽箭头chevron串联式）--- */
.pg-steps-progress-bar {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: stretch;
  padding: 10px 12px 6px;
  flex-shrink: 0;
  gap: 4px; /* 箭头之间的小间隙 */
}

/* ★ Chevron箭头：左侧V缺口 + 右侧箭头尖（clip-path多边形）— 全宽适配 */
.pg-step-arrow {
  position: relative;
  flex: 1;
  max-width: none;        /* ★ 不限制最大宽度，与对话框等宽 */
  min-width: 80px;
  height: 56px;           /* ★ 加高 */
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: default;
  transition: all 0.35s ease;
  clip-path: polygon(
    0% 0%,
    calc(100% - 22px) 0%,
    100% 50%,
    calc(100% - 22px) 100%,
    0% 100%,
    18px 50%
  );
}

/* 默认未激活状态 — 灰色 */
.pg-step-arrow {
  background: rgba(148,163,184,0.22);
  backdrop-filter: blur(8px);
}

/* 步骤标签文字 — 浅底适配 */
.pg-step-label {
  font-size: 17px;
  font-weight: 700;
  color: #94a3b8;            /* ★ 灰色（未激活状态） */
  white-space: nowrap;
  letter-spacing: 1px;
  transition: all 0.3s ease;
}

/* ===== 各步骤独立颜色（浅底玻璃拟态版）===== */

/* 步骤1 - 主蓝色 */
.pg-step-1 { background: rgba(91,141,239,0.15); }
.pg-step-1.active {
  background: linear-gradient(135deg, #6366F1, #4F46E5);
  box-shadow: 0 3px 12px rgba(91,141,239,0.3), 0 1px 4px rgba(91,141,239,0.12);
}
.pg-step-1.active .pg-step-label { color: #fff; text-shadow: 0 1px 2px rgba(0,0,0,0.15); }
.pg-step-1.completed {
  background: linear-gradient(135deg, #6366F1, #4F46E5);
}
.pg-step-1.completed .pg-step-label { color: rgba(255,255,255,0.95); }

/* 步骤2 - 深蓝 */
.pg-step-2 { background: rgba(2,136,209,0.15); }
.pg-step-2.active {
  background: linear-gradient(135deg, #4F46E5, #2C5CC5);
  box-shadow: 0 3px 12px rgba(2,136,209,0.3), 0 1px 4px rgba(2,136,209,0.12);
}
.pg-step-2.active .pg-step-label { color: #fff; text-shadow: 0 1px 2px rgba(0,0,0,0.15); }
.pg-step-2.completed {
  background: linear-gradient(135deg, #4F46E5, #2C5CC5);
}
.pg-step-2.completed .pg-step-label { color: rgba(255,255,255,0.95); }

/* 步骤3 - 蓝色（与步骤2一致） */
.pg-step-3 { background: rgba(148,163,184,0.25); }
.pg-step-3.active {
  background: linear-gradient(135deg, #4F46E5, #2C5CC5);
  box-shadow: 0 3px 12px rgba(2,136,209,0.3), 0 1px 4px rgba(2,136,209,0.12);
}
.pg-step-3.active .pg-step-label { color: #fff; text-shadow: 0 1px 2px rgba(0,0,0,0.15); }
.pg-step-3.completed {
  background: linear-gradient(135deg, #4F46E5, #2C5CC5);
}
.pg-step-3.completed .pg-step-label { color: rgba(255,255,255,0.95); }

/* 步骤4 - 蓝色（与步骤2一致） */
.pg-step-4 { background: rgba(148,163,184,0.25); }
.pg-step-4.active {
  background: linear-gradient(135deg, #4F46E5, #2C5CC5);
  box-shadow: 0 3px 12px rgba(2,136,209,0.3), 0 1px 4px rgba(2,136,209,0.12);
}
.pg-step-4.active .pg-step-label { color: #fff; text-shadow: 0 1px 2px rgba(0,0,0,0.15); }
.pg-step-4.completed {
  background: linear-gradient(135deg, #4F46E5, #2C5CC5);
}
.pg-step-4.completed .pg-step-label { color: rgba(255,255,255,0.95); }

/* 对勾图标已隐藏 */
.pg-step-check { display: none !important; }

/* --- 当前步骤描述栏（已移除） --- */
.pg-current-step-desc { display: none !important; }
.pg-hint-text { display: none !important; }

/* --- ★ 轻量Toast通知（网络错误提示等）--- */
#pg-error-toast {
  position: fixed;
  top: 20px;
  left: 50%;
  transform: translateX(-50%) translateY(-20px);
  z-index: 99999;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 22px;
  background: linear-gradient(135deg, #fff, #f8fafc);
  border: 1.5px solid rgba(239,68,68,0.3);
  border-radius: 50px;
  box-shadow: 0 4px 20px rgba(239,68,68,0.15), 0 2px 8px rgba(0,0,0,0.06);
  font-size: 14px;
  color: #991b1b;
  opacity: 0;
  transition: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  pointer-events: none;
  white-space: nowrap;
}
#pg-error-toast.pg-toast-show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}
.pg-toast-icon {
  font-size: 16px;
}
.pg-toast-text {
  font-weight: 500;
  letter-spacing: 0.5px;
}

/* --- AI 对话区域：科技玻璃拟态 --- */
.pg-dialog-area {
  flex: 1;
  min-height: 12.5rem;
  max-height: none;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: rgba(91,141,239,0.25) transparent;
  padding: 1rem 1.125rem;
  display: flex;
  flex-direction: column;
  gap: 0.875rem;
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-xl);
  box-shadow: var(--glass-shadow);
  position: relative;
}

/* ★ 对话区域内部微光 */
.pg-dialog-area::before {
  content: '';
  position: absolute;
  top: 0;
  left: 20%;
  right: 20%;
  height: 1px;
  background: linear-gradient(90deg,
    transparent,
    rgba(91,141,239,0.15),
    transparent
  );
  pointer-events: none;
}
.pg-dialog-area::-webkit-scrollbar { width: 6px; }
.pg-dialog-area::-webkit-scrollbar-track { background: transparent; }
.pg-dialog-area::-webkit-scrollbar-thumb { 
  background: linear-gradient(180deg, #6366F1, #F59E0B); 
  border-radius: 10px; 
}

/* ============================================
   ★ 聊天气泡样式：科技感升级
   ============================================ */

/* 消息气泡通用样式 */
.pg-msg {
  max-width: 82%;
  padding: 16px 22px;          /* ★ 增大内边距 */
  border-radius: 22px;         /* ★ 更圆润 */
  font-size: 15.5px;
  line-height: 1.75;
  animation: msgSlideIn 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) both;   /* ★ 更流畅动画 */
  position: relative;
  word-break: break-word;
}

@keyframes msgSlideIn {
  from { opacity: 0; transform: translateY(12px) scale(0.96); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}

/* ★ 步骤印章标签 — 已废弃 */
.pg-step-badge { display: none !important; }

/* ★ AI 助手消息：科技玻璃拟态白气泡 */
.pg-msg-ai {
  align-self: flex-start;
  background: linear-gradient(
    135deg,
    rgba(255, 255, 255, 0.85) 0%,
    rgba(255, 255, 255, 0.65) 100%
  );
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  color: #222;               /* ★ 黑色 */
  border-bottom-left-radius: 6px;   /* ★ 稍大圆角 */
  box-shadow:
    0 4px 20px rgba(99, 102, 241, 0.1),
    0 2px 6px rgba(0, 0, 0, 0.04),
    inset 0 1px 0 rgba(255,255,255,0.7);
  border: 1.5px solid rgba(99, 102, 241, 0.18);
}
/* AI气泡左侧小三角尾巴 */
.pg-msg-ai::before {
  content: '';
  position: absolute;
  left: -9px;
  bottom: 16px;
  width: 0;
  height: 0;
  border-top: 9px solid transparent;
  border-right: 11px solid rgba(255, 255, 255, 0.75);
  border-bottom: 9px solid transparent;
  filter: drop-shadow(-2px 1px 1px rgba(0,0,0,0.04));
}

/* ★ 用户消息：主色渐变 + 发光效果 */
.pg-msg-user {
  align-self: flex-end;
  background: linear-gradient(
    135deg,
    #6366F1 0%,
    #4F46E5 50%,
    #4338CA 100%
  );
  color: #ffffff;
  border-bottom-right-radius: 6px;
  box-shadow:
    0 4px 20px rgba(99, 102, 241, 0.3),
    0 2px 8px rgba(99, 102, 241, 0.15),
    inset 0 1px 0 rgba(255,255,255,0.2);
  border: none;
}
/* 用户气泡右侧小三角尾巴 */
.pg-msg-user::after {
  content: '';
  position: absolute;
  right: -9px;
  bottom: 16px;
  width: 0;
  height: 0;
  border-top: 9px solid transparent;
  border-left: 11px solid #4F46E5;
  border-bottom: 9px solid transparent;
  filter: drop-shadow(2px 1px 1px rgba(0,0,0,0.06));
}

.pg-step-arrow.completed {
  background: linear-gradient(135deg, rgba(52,211,153,0.95), rgba(16,185,129,0.85)) !important;
  color: #fff !important;
}

.pg-step-arrow.completed .pg-step-check {
  opacity: 1;
  transform: scale(1);
}

/* AI 消息中的引导提示高亮 */
.pg-msg-hint {
  margin-top: 12px;
  padding: 12px 16px;
  background: linear-gradient(
    135deg,
    rgba(91,141,239,0.1) 0%,
    rgba(179,229,252,0.08) 100%
  );
  border-left: 3px solid #6366F1;
  border-radius: 0 12px 12px 0;
  font-size: 14px;
  color: #222;               /* ★ 黑色 */
  line-height: 1.65;
}

/* 打字动画光标 */
.pg-typing-cursor::after {
  content: '▋';
  animation: blinkCursor 0.7s infinite;
  color: #4caf50;
  margin-left: 2px;
}
@keyframes blinkCursor {
  0%,100% { opacity: 1; }
  50%      { opacity: 0; }
}

/* --- ★ 步骤完成小结卡片 — 玻璃拟态浅蓝风 --- */
.pg-step-summary {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 20px;
  margin: 8px 0;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1.5px solid rgba(99, 102, 241, 0.2);
  border-radius: 14px;
  box-shadow: 0 2px 12px rgba(99, 102, 241, 0.08), 0 1px 3px rgba(0,0,0,0.02);
  animation: summarySlideIn 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes summarySlideIn {
  from { 
    opacity: 0; 
    transform: translateX(-20px) scale(0.95); 
  }
  to   { 
    opacity: 1; 
    transform: translateX(0) scale(1); 
  }
}

.pg-summary-icon {
  font-size: 28px;
  flex-shrink: 0;
}

/* ★ 波利亚正在思考动画 */
.pg-thinking {
  align-self: flex-start;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 20px;
  background: linear-gradient(135deg, rgba(245, 158, 11, 0.08) 0%, rgba(99, 102, 241, 0.06) 100%);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1.5px solid rgba(245, 158, 11, 0.25);
  border-radius: 18px;
  border-bottom-left-radius: 6px;
  animation: thinkingPulse 2s ease-in-out infinite;
}
.pg-thinking-text {
  font-size: 14px;
  color: #8B6914;
  font-weight: 500;
  letter-spacing: 0.5px;
}
.pg-thinking-dots {
  display: flex;
  gap: 4px;
  align-items: center;
}
.pg-thinking-dots span {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: #F59E0B;
  animation: dotBounce 1.2s ease-in-out infinite;
}
.pg-thinking-dots span:nth-child(2) { animation-delay: 0.2s; }
.pg-thinking-dots span:nth-child(3) { animation-delay: 0.4s; }

@keyframes dotBounce {
  0%, 60%, 100% { transform: translateY(0); opacity: 0.4; }
  30% { transform: translateY(-8px); opacity: 1; }
}
@keyframes thinkingPulse {
  0%, 100% { box-shadow: 0 2px 12px rgba(245, 158, 11, 0.1), 0 1px 3px rgba(0,0,0,0.03); }
  50% { box-shadow: 0 4px 20px rgba(245, 158, 11, 0.2), 0 2px 6px rgba(0,0,0,0.05); }
}

/* ★ 语音消息气泡 */
.pg-msg-voice {
  flex-direction: column;
  gap: 8px;
  align-items: flex-end;
}
.pg-voice-text {
  font-size: 15px;
  color: #222;
  line-height: 1.5;
  word-break: break-word;
}
.pg-voice-replay {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 5px 14px;
  font-size: 13px;
  color: #5B8DEF;
  background: rgba(91, 141, 239, 0.08);
  border: 1px solid rgba(91, 141, 239, 0.2);
  border-radius: 20px;
  cursor: pointer;
  transition: all 0.2s;
}
.pg-voice-replay:hover {
  background: rgba(91, 141, 239, 0.16);
  border-color: rgba(91, 141, 239, 0.4);
}

/* ★ 录音按钮脉冲动画 */
.pg-voice-icon.recording {
  animation: voicePulse 1.2s ease-in-out infinite;
  color: #EF4444;
}
@keyframes voicePulse {
  0%, 100% { transform: scale(1); box-shadow: 0 0 0 0 rgba(239,68,68,0.4); }
  50% { transform: scale(1.1); box-shadow: 0 0 0 8px rgba(239,68,68,0); }
}

.pg-summary-content {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.pg-summary-label {
  font-size: 15px;
  font-weight: 700;
  color: #DAA520;            /* ★ 金色 */
  letter-spacing: 0.5px;
}

/* --- ★ AI 提示消息 — 浅蓝玻璃拟态气泡 --- */
.pg-msg-ai-hint {
  max-width: 85%;
  padding: 14px 20px;
  border-radius: 20px;
  font-size: 15.5px;
  line-height: 1.7;
  background: linear-gradient(135deg, rgba(227,242,253,0.9) 0%, rgba(179,229,252,0.7) 100%);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1.5px solid rgba(99, 102, 241, 0.25);
  border-bottom-left-radius: 4px;
  color: #222;               /* ★ 黑色 */
  box-shadow:
    0 3px 14px rgba(99, 102, 241, 0.1),
    0 1px 4px rgba(0, 0, 0, 0.04);
}
/* 气泡左侧小三角尾巴 */
.pg-msg-ai-hint::after {
  content: '';
  position: absolute;
  left: -8px;
  bottom: 16px;
  width: 0; height: 0;
  border-top: 8px solid transparent;
  border-right: 10px solid rgba(179,229,252,0.7);
  border-bottom: 8px solid transparent;
  filter: drop-shadow(-2px 1px 1px rgba(0,0,0,0.03));
}
.pg-msg-ai-hint .hint-label,
.pg-msg-ai-hint > span:first-child {
  display: block;
  font-weight: 700;
  color: #DAA520;            /* ★ 金色 */
  font-size: 13px;
}

/* --- 底部输入区：科技玻璃拟态 --- */
.pg-input-area {
  flex-shrink: 0;
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-xl);
  padding: 1rem 1.25rem;
  position: relative;
  overflow: hidden;
}

/* ★ 输入区顶部微光 */
.pg-input-area::before {
  content: '';
  position: absolute;
  top: 0;
  left: 15%;
  right: 15%;
  height: 1px;
  background: linear-gradient(90deg,
    transparent,
    rgba(91,141,239,0.12),
    transparent
  );
  pointer-events: none;
}

.pg-input-row {
  display: flex;
  gap: 12px;                   /* ★ 增大间距 */
  align-items: center;
}

/* ★ 输入框包裹容器 */
.pg-input-wrapper {
  position: relative;
  flex: 1;
  display: flex;
  align-items: center;
}

.pg-user-input {
  width: 100%;
  padding: 0.8125rem 5.125rem 0.8125rem 1.125rem;
  font-size: 0.96875rem;
  min-height: var(--input-height);
  background: linear-gradient(
    to bottom,
    rgba(255, 255, 255, 0.92) 0%,
    rgba(255, 255, 255, 0.78) 100%
  );
  border: 2px solid rgba(99, 102, 241, 0.25);
  border-radius: var(--radius-md);
  outline: none;
  color: #333;
  transition: all 0.3s ease;
  box-sizing: border-box;
  box-shadow: inset 0 1px 2px rgba(0,0,0,0.04);
}
.pg-user-input:focus {
  border-color: #6366F1;
  box-shadow:
    0 0 0 3px rgba(99, 102, 241, 0.15),
    inset 0 1px 2px rgba(0,0,0,0.02);
}

.pg-send-btn {
  padding: 0.6875rem 1.625rem;
  font-size: 0.9375rem;
  font-weight: 700;
  min-height: var(--btn-height);
  color: #fff;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.25s ease;
  white-space: nowrap;
  box-shadow: 0 3px 10px rgba(99, 102, 241, 0.25), 0 1px 4px rgba(99, 102, 241, 0.1);
}
.pg-send-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(99, 102, 241, 0.35), 0 2px 8px rgba(99, 102, 241, 0.15);
}
.pg-send-btn:active { transform: translateY(0); }
.pg-send-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

/* --- 输入框内嵌图标（拍照 + 语音）— 大号醒目版 --- */
.pg-input-icon {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  font-size: 22px;
  font-weight: 600;
  background: linear-gradient(135deg, #6366F1, #4F46E5);
  color: #fff;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.25s ease;
  box-shadow: 0 3px 10px rgba(91,141,239,0.35);
}
.pg-input-icon:hover {
  background: linear-gradient(135deg, #4F46E5, #2C5CC5);
  transform: translateY(-50%) scale(1.06);
  box-shadow: 0 5px 16px rgba(91,141,239,0.5);
}
.pg-img-icon { right: 56px; }   /* 拍照靠右 */
.pg-voice-icon { right: 4px; }    /* 语音最右 */

/* ★ 语音正在录音 — 红色脉冲 + 大号提示 */
.pg-voice-icon.recording {
  color: #fff;
  background: linear-gradient(135deg, #ef4444, #dc2626);
  font-size: 22px;
  box-shadow: 0 3px 10px rgba(239,68,68,0.45);
  animation: voiceRecordPulse 1s ease-in-out infinite;
}
@keyframes voiceRecordPulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(239, 68, 68, 0.5); transform: translateY(-50%) scale(1); }
  50%      { box-shadow: 0 0 0 10px rgba(239, 68, 68, 0); transform: translateY(-50%) scale(1.12); }
}

/* ★ 语音录音时输入框也变红框提示 */
.pg-user-input.voice-active {
  border-color: #ef4444 !important;
  box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.15) !important;
}
.pg-voice-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(16, 185, 129, 0.4);
}
.pg-voice-btn:active { transform: translateY(0); }
.pg-voice-btn.recording {
  animation: voicePulse 1.2s ease-in-out infinite;
  background: linear-gradient(135deg, #ef4444, #dc2626);
}
@keyframes voicePulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(239, 68, 68, 0.5); }
  50% { box-shadow: 0 0 0 12px rgba(239, 68, 68, 0); }
}

/* --- ★ 语音消息气泡 --- */
.pg-voice-msg {
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-width: 300px;
}
.pg-voice-player {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  background: linear-gradient(135deg, #6366F1, #4F46E5);
  border-radius: 20px;
  cursor: pointer;
  transition: all 0.2s ease;
}
.pg-voice-player:hover {
  box-shadow: 0 3px 12px rgba(91,141,239,0.3);
  transform: scale(1.02);
}
.pg-voice-play-icon {
  width: 34px; height: 34px; min-width: 34px;
  background: rgba(255,255,255,0.25); border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 15px; color: #fff; transition: all 0.2s ease;
}
.pg-voice-playing .pg-voice-play-icon {
  background: rgba(255,255,255,0.35);
}
.pg-voice-waveform {
  flex: 1; display: flex; align-items: center; gap: 2px; height: 24px;
}
.pg-voice-bar {
  width: 3px; background: rgba(255,255,255,0.6); border-radius: 2px;
  transition: height 0.15s ease;
}
.pg-voice-playing .pg-voice-bar {
  animation: waveAnim 0.6s ease-in-out infinite alternate;
}
.pg-voice-bar:nth-child(1) { animation-delay: 0s; }
.pg-voice-bar:nth-child(2) { animation-delay: 0.1s; }
.pg-voice-bar:nth-child(3) { animation-delay: 0.2s; }
.pg-voice-bar:nth-child(4) { animation-delay: 0.05s; }
.pg-voice-bar:nth-child(5) { animation-delay: 0.15s; }
.pg-voice-bar:nth-child(6) { animation-delay: 0.25s; }
.pg-voice-bar:nth-child(7) { animation-delay: 0.08s; }
.pg-voice-bar:nth-child(8) { animation-delay: 0.18s; }

@keyframes waveAnim {
  0%   { height: 5px; }
  100% { height: var(--max-h, 20px); }
}

.pg-voice-duration {
  font-size: 11px; color: rgba(255,255,255,0.85); min-width: 28px; text-align: right;
}

/* ★ 语音转录文字 */
.pg-voice-transcript {
  font-size: 13px; color: #475569; padding: 0 4px; line-height: 1.5;
}

/* --- 提示按钮（需要帮助时点击）--- */
.pg-hint-btn {
  padding: 11px 18px;
  font-size: 14px;
  font-weight: 600;
  color: #fff;
  background: linear-gradient(135deg, #f59e0b, #ea580c);
  border: none;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.25s ease;
  white-space: nowrap;
}
.pg-hint-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(245, 158, 11, 0.4);
}
.pg-hint-btn:active { transform: translateY(0); }
.pg-hint-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* --- 快捷演示按钮 --- */
.pg-demo-btn {
  padding: 11px 18px;
  font-size: 14px;
  font-weight: 600;
  color: #fff;
  background: linear-gradient(135deg, #10b981, #059669);
  border: none;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.25s ease;
  white-space: nowrap;
}
.pg-demo-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(16, 185, 129, 0.4);
}
.pg-demo-btn:active { transform: translateY(0); }
.pg-demo-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* ==================== ★ TTS 语音朗读开关按钮 ==================== */
.tts-toggle-btn {
  padding: 11px 16px;
  font-size: 20px;
  font-weight: 700;
  color: #fff;
  background: linear-gradient(135deg, #6366F1, #4F46E5);
  border: none;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.3s ease;
  white-space: nowrap;
  line-height: 1;
  min-width: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 3px 12px rgba(99, 102, 241, 0.3), 0 1px 4px rgba(0, 0, 0, 0.08);
}
.tts-toggle-btn:hover {
  transform: translateY(-2px) scale(1.08);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.45), 0 2px 8px rgba(0, 0, 0, 0.12);
}
.tts-toggle-btn:active { transform: translateY(0) scale(0.98); }

/* ★ 正在朗读时的脉冲动画 */
.tts-toggle-btn.tts-speaking {
  background: linear-gradient(135deg, #FF9800, #F57C00);
  box-shadow: 0 3px 16px rgba(255, 152, 0, 0.5), 0 1px 4px rgba(0, 0, 0, 0.1);
  animation: ttsSpeakPulse 1.2s ease-in-out infinite;
}
@keyframes ttsSpeakPulse {
  0%, 100% { transform: scale(1); box-shadow: 0 3px 16px rgba(255, 152, 0, 0.5); }
  50% { transform: scale(1.1); box-shadow: 0 5px 24px rgba(255, 152, 0, 0.7); }
}

/* ★ 静音状态 */
.tts-toggle-btn.tts-muted {
  background: linear-gradient(135deg, #9e9e9e, #757575);
  box-shadow: none;
  opacity: 0.65;
}
.tts-toggle-btn.tts-muted:hover {
  opacity: 1;
  transform: translateY(-2px) scale(1.05);
}

.pg-hint-text {
  margin-top: 8px;
  font-size: 12.5px;
  color: #555;               /* ★ 深灰黑 */
  text-align: center;
  font-style: italic;
}

/* --- 答题后双按钮区域 --- */
.post-submit-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px dashed rgba(255, 255, 255, 0.15);
}

.post-btn {
  padding: 11px 28px;
  font-size: 15px;
  font-weight: 700;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.3s ease;
  letter-spacing: 1px;
}

.post-btn-continue {
  color: #fff;
  background: linear-gradient(135deg, #6366F1, #4338CA);
}
.post-btn-continue:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(99, 102, 241, 0.4);
}

.post-btn-analyze {
  color: #fff;
  background: linear-gradient(135deg, #F59E0B, #EA580C);   /* ★ 辅色渐变 */
}
.post-btn-analyze:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(245, 87, 108, 0.4);
}

/* --- 完成状态区域 — 浅色模糊遮罩 --- */
.pg-completion-area {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  z-index: 9999;
  background: rgba(227, 242, 253, 0.5);
  backdrop-filter: blur(10px);
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 8vh;
  padding-left: 20px;
  padding-right: 20px;
  overflow-y: auto;
}

.pg-completion-icon {
  font-size: 56px;
  margin-bottom: 12px;
}

.pg-completion-title {
  font-size: 22px;
  font-weight: 800;
  color: #DAA520;            /* ★ 金色 */
  margin-bottom: 8px;
}

.pg-completion-desc {
  font-size: 15px;
  color: #444;               /* ★ 黑色（稍浅） */
  margin-bottom: 24px;
  line-height: 1.6;
}

.pg-completion-actions {
  display: flex;
  gap: 14px;
  justify-content: center;
  margin-bottom: 20px;
}

.pg-action-btn {
  padding: 12px 30px;
  font-size: 15px;
  font-weight: 700;
  border: none;
  border-radius: 14px;
  cursor: pointer;
  transition: all 0.3s ease;
  letter-spacing: 1px;
}

.pg-btn-primary {
  color: #fff;
  background: linear-gradient(135deg, #6366F1, #4F46E5);   /* ★ 主色渐变 */
}
.pg-btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.35), 0 2px 8px rgba(99, 102, 241, 0.15);
}

.pg-btn-secondary {
  color: #DAA520;            /* ★ 金色 */
  border: 1.5px solid rgba(99, 102, 241, 0.25);
}
.pg-btn-secondary:hover {
  background: rgba(255, 255, 255, 0.8);
  transform: translateY(-2px);
}

.pg-answer-display {
  margin-top: 20px;
  text-align: left;
  animation: fadeInUp 0.4s ease both;
}

/* ============================================
   ★ 完成状态：总结弹窗样式（三阶段递进）
   ============================================ */

/* 弹窗遮罩层（父级pg-completion-area已为fixed全屏，此处仅作弹窗定位容器） */
.pg-summary-overlay {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  width: 100%;
  /* 不再需要 position: fixed，由父级 pg-completion-area 提供 */
}

/* 弹窗主体 — 玻璃拟态白色主题 */
.pg-summary-popup {
  width: 100%;
  max-width: 35rem;
  max-height: 82vh;
  overflow-y: auto;
  background: var(--glass-bg-hover);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-radius: var(--radius-xl);
  border: 1.5px solid var(--glass-border-subtle);
  box-shadow:
    0 16px 48px rgba(99, 102, 241, 0.12),
    0 4px 16px rgba(0, 0, 0, 0.06),
    var(--glass-inset);
  padding: 1.625rem 1.625rem 1.375rem;
  color: var(--color-text-primary);
  margin-bottom: 6vh;
}
.pg-summary-popup::-webkit-scrollbar { width: 5px; }
.pg-summary-popup::-webkit-scrollbar-track { background: transparent; }
.pg-summary-popup::-webkit-scrollbar-thumb { background: rgba(99, 102, 241,0.2); border-radius: 10px; }

/* ★ 各阶段独立区域（默认隐藏，由JS控制显示） */
.pg-summary-section {
  animation: fadeInUp 0.4s ease both;
}

/* 总结头部 — 浅蓝主题 */
.pg-summary-header { text-align: center; margin-bottom: 18px; }
.pg-summary-header h3 {
  font-size: 21px; margin: 6px 0 0;
  background: linear-gradient(135deg, #FFD700, #F59E0B, #FFB300);   /* ★ 金色渐变 */
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: 2.5px; font-weight: 800;
}
.pg-summary-icon { font-size: 34px; display: block; }

/* 总结内容区 — 浅蓝玻璃拟态 */
.pg-summary-body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
  background: rgba(227,242,253,0.6);
  border: 1.5px solid rgba(91,141,239,0.12);
  border-radius: 14px;
  padding: 16px 18px; margin-bottom: 14px;
  font-size: 14px; line-height: 1.7; color: #222;    /* ★ 黑色 */
}
.pg-thought-intro { margin-bottom: 14px; color: #555; font-size: 13px; text-align: center; }

/* ★ 大模型思考中加载态 — 浅蓝主题 */
.pg-thinking-loader {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 36px 16px;
  gap: 14px;
}
.pg-thinking-img {
  width: 80px;
  height: auto;
  opacity: 0.9;
  animation: pg-thinking-bounce 1.4s ease-in-out infinite;
}
@keyframes pg-thinking-bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}
.pg-thinking-text {
  font-size: 15px;
  color: #DAA520;            /* ★ 金色 */
  letter-spacing: 2px;
  animation: pg-thinking-pulse 1.6s ease-in-out infinite;
}
@keyframes pg-thinking-pulse {
  0%, 100% { opacity: 0.6; }
  50% { opacity: 1; }
}

/* ★ AI 生成的解题思路步骤卡片 — 浅蓝玻璃拟态主题 */
.pg-thought-steps {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.ai-step-card {
  background: rgba(255, 255, 255, 0.65);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-radius: 12px;
  border-left: 4px solid;
  padding: 13px 16px;
  transition: all 0.25s ease;
  box-shadow: 0 1px 6px rgba(99, 102, 241, 0.05);
}
.ai-step-card[data-step="1"] { border-color: #6366F1; background: linear-gradient(135deg, rgba(227,242,253,0.7), rgba(255,255,255,0.5)); }
.ai-step-card[data-step="2"] { border-color: #4F46E5; background: linear-gradient(135deg, rgba(179,229,252,0.5), rgba(255,255,255,0.45)); }
.ai-step-card[data-step="3"] { border-color: #F59E0B; background: linear-gradient(135deg, rgba(255,248,225,0.7), rgba(255,255,255,0.5)); }
.ai-step-card[data-step="4"] { border-color: #EA580C; background: linear-gradient(135deg, rgba(255,235,205,0.55), rgba(255,255,255,0.4)); }
.ai-step-card:hover { box-shadow: 0 4px 14px rgba(99, 102, 241, 0.1); transform: translateX(4px) !important; }

.ai-step-title {
  font-size: 14.5px;
  font-weight: 700;
  margin-bottom: 6px;
}
.ai-step-card[data-step="1"] .ai-step-title { color: #DAA520; }     /* ★ 金色 */
.ai-step-card[data-step="2"] .ai-step-title { color: #01579b; }
.ai-step-card[data-step="3"] .ai-step-title { color: #F57F17; }
.ai-step-card[data-step="4"] .ai-step-title { color: #E65100; }

.ai-step-body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
  font-size: 13.5px;
  line-height: 1.75;
  color: #222;               /* ★ 黑色 */
}
.ai-step-body p { margin: 4px 0; }

/* ★ 学习过程总评卡片 */
.pg-process-summary {
  margin-top: 16px;
  padding: 16px 18px;
  background: linear-gradient(135deg, rgba(16, 185, 129, 0.08), rgba(240, 253, 244, 0.7));
  border: 1.5px solid rgba(16, 185, 129, 0.3);
  border-radius: 14px;
  box-shadow: 0 2px 12px rgba(16, 185, 129, 0.08);
}
.pg-ps-title {
  font-size: 15px;
  font-weight: 700;
  color: #166534;
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 6px;
}
.pg-ps-body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
  font-size: 13.5px;
  line-height: 1.8;
  color: #222;               /* ★ 黑色 */
}
.pg-ps-body p { margin: 6px 0; }

.pg-thought-keypoint {
  margin-top: 12px; padding: 12px 14px;
  background: linear-gradient(135deg, rgba(91,141,239,0.06), rgba(243,246,255,0.7));
  border-left: 3px solid #6366F1;              /* ★ 主色 */
  border-radius: 0 10px 10px 0;
  font-size: 13px; color: #222;             /* ★ 黑色 */
}

/* ★ 顶部操作按钮 — 蓝色居中主题 */
.pg-summary-actions-top {
  display: flex;
  justify-content: center;
  margin-bottom: 12px;
}
.pg-btn-solution, .pg-btn-analysis {
  display: block;
  width: auto;
  padding: 12px 36px;
  border-radius: 14px;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.3s ease;
  border: none;
  letter-spacing: 1px;
  background: linear-gradient(135deg, #6366F1, #4338CA);   /* ★ 主色渐变 */
  color: #fff;
  box-shadow: 0 4px 16px rgba(99, 102, 241,0.35);
  text-align: center;
}
.pg-btn-solution:hover, .pg-btn-analysis:hover { 
  transform: translateY(-2px); 
  box-shadow: 0 6px 22px rgba(99, 102, 241, 0.45);    /* ★ 主色阴影 */
}

/* 完整解析面板（阶段2使用）— 白色主题 */
.pg-full-solution {
  background: #ffffff;
  border: 2px solid rgba(99, 102, 241,0.18);
  border-radius: 14px;
  padding: 18px 20px;
  margin-bottom: 14px;
  animation: fadeInUp 0.35s ease both;
  box-shadow: 0 2px 12px rgba(99, 102, 241,0.08);
}
.pg-solution-title {
  color: #B8860B; font-size: 16px; margin-bottom: 12px; padding-bottom: 8px;
  font-weight: 700; letter-spacing: 1px;
  border-bottom: 1.5px solid rgba(99, 102, 241,0.18);
}
.solution-text {
  font-size: 14.5px;
  line-height: 2;
  color: #222;               /* ★ 黑色 */
  text-align: left;
  padding: 8px 12px;
  background: rgba(243,246,255,0.7);
  border: 1.5px solid rgba(99, 102, 241,0.12);
  border-radius: 10px;
}
/* 解析每一步独立一行 */
.solution-line {
  display: inline-block;
  padding: 2px 8px;
}
.solution-answer {
  margin-top: 14px; padding: 14px 18px;
  background: linear-gradient(135deg, rgba(99, 102, 241,0.08), rgba(243,246,255,0.7));
  border: 1.5px solid rgba(99, 102, 241,0.25);
  border-radius: 11px; font-size: 15.5px; color: #1e40af;
  font-weight: 700;
}

/* 做题分析面板（阶段3使用）— 白色主题 */
.pg-analysis-panel {
  background: #ffffff;
  border: 1.5px solid rgba(99, 102, 241,0.15);
  border-radius: 14px;
  padding: 16px 18px;
  margin-bottom: 12px;
  animation: fadeInUp 0.35s ease both;
  box-shadow: 0 2px 10px rgba(99, 102, 241,0.06);
}
/* ★ 分析卡片列表容器（复用思路梳理的 flex 列布局） */
.pg-analysis-steps {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
/* ★ 做题分析专用卡片配色 — 蓝白主题 */
.ai-step-card[data-step="a1"] {
  border-color: #27ae60;
  background: linear-gradient(135deg, rgba(39,174,96,0.05), #ffffff);
}
.ai-step-card[data-step="a1"] .ai-step-title { color: #16a34a; }

.ai-step-card[data-step="a2"] {
  border-color: #f59e0b;
  background: linear-gradient(135deg, rgba(245,158,11,0.05), #ffffff);
}
.ai-step-card[data-step="a2"] .ai-step-title { color: #d97706; }

.ai-step-card[data-step="a3"] {
  border-color: #5b8def;
  background: linear-gradient(135deg, rgba(91,141,239,0.05), #ffffff);
}
.ai-step-card[data-step="a3"] .ai-step-title { color: #2563eb; }

/* ★ 卡片内列表统一样式 — 白色主题 */
.ai-step-card ul,
.ai-step-card ol {
  margin: 0;
  padding-left: 20px;
  font-size: 13.5px;
  line-height: 1.78;
  color: #222;               /* ★ 黑色 */
}
.ai-step-card li { margin-bottom: 4px; }

/* ★ 底部导航按钮 — 蓝色居中主题 */
.pg-summary-actions-bottom {
  display: flex;
  gap: 14px;
  margin-top: 18px;
  padding-top: 18px;
  border-top: 1.5px solid rgba(99, 102, 241,0.12);
  justify-content: center;
}
.pg-nav-btn {
  display: block;
  min-width: 160px;
  padding: 13px 28px;
  border-radius: 14px;
  font-size: 14.5px;
  font-weight: 700;
  cursor: pointer;
  border: none;
  transition: all 0.3s ease;
  letter-spacing: 0.5px;
  text-align: center;
  background: linear-gradient(135deg, #6366F1, #4338CA);   /* ★ 主色渐变 */
  color: #fff;
  box-shadow: 0 4px 16px rgba(99, 102, 241,0.35);
}
.pg-nav-btn:hover { 
  transform: translateY(-2px); 
  box-shadow: 0 6px 22px rgba(99, 102, 241, 0.45);     /* ★ 主色阴影 */
}


/* ============================================
   ★ 递进式错误引导样式
   ============================================ */

/* 第一次错 — 选项卡片（玻璃拟态） */
.pg-progress-help {
  background: linear-gradient(145deg, rgba(227,242,253,0.7), rgba(179,229,252,0.5)) !important;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1.5px solid rgba(91,141,239,0.2) !important;
  border-radius: 14px !important; padding: 16px 18px !important;
  margin-top: 12px !important; animation: fadeInUp 0.35s ease both;
}
.pg-help-header { font-size: 14px; font-weight: 700; color: #DAA520; margin-bottom: 12px; }   /* ★ 金色 */
.pg-help-option {
  display: flex; align-items: center; gap: 10px;
  padding: 10px 14px; margin-bottom: 8px;
  background: rgba(255,255,255,0.45);
  border: 1.5px solid rgba(91,141,239,0.15);
  border-radius: 10px; cursor: pointer; transition: all 0.25s ease;
}
.pg-help-option:hover {
  background: rgba(91,141,239,0.1); border-color: rgba(91,141,239,0.35);   /* ★ 主色 */
  transform: translateX(4px);
}
.pg-opt-icon {
  flex-shrink: 0; width: 26px; height: 26px; border-radius: 50%;
  background: linear-gradient(135deg, #6366F1, #4F46E5);    /* ★ 主色渐变 */
  display: flex; align-items: center; justify-content: center;
  font-size: 12.5px; font-weight: 800; color: #fff;
}
.pg-opt-text { font-size: 13.5px; color: #333; line-height: 1.5; }

/* ====== 苏格拉底式选项卡片（两选项选择）— 玻璃拟态 ====== */
.pg-option-card {
  background: linear-gradient(145deg, rgba(227,242,253,0.65), rgba(179,229,252,0.45)) !important;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1.5px solid rgba(91,141,239,0.2) !important;
  border-radius: 16px !important; padding: 18px 20px !important;
  margin-top: 14px !important; animation: fadeInUp 0.35s ease both;
}
.pg-option-hint {
  font-size: 14px; font-weight: 600; color: #DAA520;     /* ★ 金色 */
  margin-bottom: 12px;
}
.pg-option-list { display: flex; flex-direction: column; gap: 10px; }
.pg-socratic-option {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 16px; cursor: pointer;
  background: rgba(255,255,255,0.5);
  border: 1.5px solid rgba(91,141,239,0.15);
  border-radius: 12px; transition: all 0.25s ease;
}
.pg-socratic-option:hover {
  background: rgba(255,255,255,0.7);
  border-color: rgba(91,141,239,0.35);
  transform: translateX(6px) scale(1.02);
  box-shadow: 0 4px 14px rgba(91,141,239,0.12), 0 2px 6px rgba(0,0,0,0.04);
}
.pg-sopt-letter {
  flex-shrink: 0; width: 30px; height: 30px; border-radius: 8px;
  background: linear-gradient(135deg, #6366F1, #4F46E5);    /* ★ 主色渐变 */
  display: flex; align-items: center; justify-content: center;
  font-size: 14px; font-weight: 800; color: #fff;
}
.pg-sopt-text {
  font-size: 14px; color: #222; line-height: 1.6;            /* ★ 黑色 */
}

/* 第二次错 — 直接提示（浅黄玻璃拟态） */
.pg-hint-level2 {
  background: linear-gradient(145deg, rgba(255,248,225,0.7), rgba(255,235,205,0.5)) !important;
  backdrop-filter: blur(10px);
  border: 1.5px solid rgba(255,193,7,0.25) !important;
  border-radius: 14px !important; padding: 16px 18px !important;
  margin-top: 12px !important; animation: fadeInUp 0.35s ease both;
}
.pg-hint-list { margin: 10px 0; padding-left: 20px; font-size: 13.5px; line-height: 1.8; color: #222; }
.pg-hint-list li { margin-bottom: 6px; }
.pg-hint-footer {
  margin-top: 12px; padding: 10px 14px;
  background: rgba(255,255,255,0.06); border-radius: 8px;
  font-size: 12.5px; color: #555; font-style: italic;          /* ★ 深灰黑 */
}

/* 第三次+错 — 鼓励表达模式（浅粉玻璃拟态） */
.pg-encourage-mode {
  background: linear-gradient(145deg, rgba(252,231,243,0.65), rgba(248,187,208,0.4)) !important;
  backdrop-filter: blur(10px);
  border: 1.5px solid rgba(240,147,251,0.2) !important;
  border-radius: 14px !important; padding: 18px 20px !important;
  margin-top: 12px !important; animation: fadeInUp 0.35s ease both; line-height: 1.7;
}
.pg-encourage-mode p { font-size: 14px; color: #222; margin-bottom: 8px; }
.pg-encourage-mode strong { color: #c62828; }   /* ★ 深红 */
.pg-think-prompt { margin: 12px 0; padding-left: 20px; font-size: 13.5px; color: #444; }
.pg-think-prompt li { margin-bottom: 5px; }
.pg-encourage-note {
  margin-top: 10px; padding: 8px 12px;
  background: rgba(252,231,243,0.5); border-radius: 8px;
  font-size: 12.5px !important; color: #AD1457 !important;
}

/* ============================================
   ★ 错题本按钮 + 弹窗样式
   ============================================ */

/* 错题本按钮（左下角悬浮） — 玻璃拟态 */
.mistake-btn {
  position: fixed;
  bottom: 1.5rem;
  right: 1.25rem;
  z-index: 500;
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 10px 16px;
  background: linear-gradient(135deg, rgba(239,83,80,0.75), rgba(211,47,47,0.65));
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1.5px solid rgba(239,83,80,0.2);
  border-radius: 14px;
  color: #fff;
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 18px rgba(239, 83, 80, 0.2), 0 1px 5px rgba(0,0,0,0.05);
}
.mistake-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 28px rgba(229, 57, 53, 0.45);
}

/* 错题本角标 */
.mistake-badge {
  display: none;
  min-width: 18px;
  height: 18px;
  line-height: 18px;
  text-align: center;
  background: #F59E0B;           /* ★ 辅色琥珀黄 */
  color: #b71c1c;
  font-size: 11px;
  font-weight: 800;
  border-radius: 50%;
  padding: 0 4px;
}

/* 错题本弹窗遮罩：柔和模糊 */
.mistake-overlay {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(227,242,253,0.4);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 9999;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 6vh;
  overflow-y: auto;
  animation: fadeIn 0.25s ease both;
}
.mistake-overlay.hidden { display: none !important; }

/* ★ 错题本弹窗：科技玻璃拟态白卡片 */
.mistake-popup {
  width: 100%;
  max-width: 38.75rem;
  max-height: 82vh;
  background: var(--glass-bg-hover);
  backdrop-filter: blur(28px);
  -webkit-backdrop-filter: blur(28px);
  border-radius: var(--radius-xl);
  border: 1.5px solid rgba(229,115,115,0.2);
  box-shadow:
    0 20px 60px rgba(229,57,53,0.12),
    0 6px 20px rgba(0,0,0,0.08),
    var(--glass-inset);
  padding: 1.75rem 1.75rem 1.5rem;
  color: var(--color-text-primary);
  margin-bottom: 4vh;
  overflow-y: auto;
  position: relative;
}

/* ★ 弹窗顶部微光 */
.mistake-popup::before {
  content: '';
  position: absolute;
  top: 0;
  left: 15%;
  right: 15%;
  height: 1px;
  background: linear-gradient(90deg,
    transparent,
    rgba(229,115,115,0.2),
    transparent
  );
  pointer-events: none;
}

.mistake-popup::-webkit-scrollbar { width: 6px; }
.mistake-popup::-webkit-scrollbar-thumb {
  background: linear-gradient(180deg, #ef4444, #f87171);
  border-radius: 10px;
}

/* 弹窗头部 */
.mistake-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 18px;
  padding-bottom: 12px;
  border-bottom: 1.5px solid rgba(229,115,115,0.15);
}
.mistake-header h3 {
  font-size: 19px;
  color: #DAA520;            /* ★ 金色 */
  letter-spacing: 1.5px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.mistake-close {
  width: 32px; height: 32px;
  border-radius: 50%;
  border: 1.5px solid rgba(229,115,115,0.2);
  background: rgba(229,115,115,0.06);
  color: #c62828;
  font-size: 18px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
}
.mistake-close:hover { background: rgba(229,57,53,0.12); color: #b71c1c; }

/* 空状态 */
.mistake-empty { text-align: center; padding: 40px 20px; color: #777; }    /* ★ 深灰 */
.mistake-empty-icon { font-size: 48px; display: block; margin-bottom: 12px; }

/* 单条错题 — 玻璃拟态 */
.mistake-item {
  background: rgba(229,115,115,0.06);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-radius: 12px;
  padding: 14px 16px;
  margin-bottom: 12px;
  border-left: 3px solid rgba(229,115,115,0.35);
  transition: all 0.2s ease;
}
.mistake-item:hover { background: rgba(229,115,115,0.1); border-left-color: #c62828; }
.mistake-item-q { font-size: 14px; line-height: 1.65; color: #1a1a1a; margin-bottom: 8px; }
.mistake-item-a { font-size: 13px; color: #1b5e20; padding-top: 8px; border-top: 1px solid rgba(229,115,115,0.15); }
/* 点击跳转提示 */
.mistake-item-action {
  margin-top: 10px;
  font-size: 12.5px;
  color: #F57C00;            /* ★ 橙色 */
  text-align: center;
  padding: 6px 0;
  border-top: 1px dashed rgba(229,115,115,0.15);
  cursor: pointer;
  transition: all 0.2s ease;
  letter-spacing: 1px;
}
.mistake-item:hover .mistake-item-action {
  color: #E65100;
  background: rgba(229,115,115,0.04);
}

/* ============================================
   ★ 第七页：P7 拍照解题界面
   设计语言与 P6 波利亚引导页保持一致：
   - 同款渐变背景
   - 白底卡片窗口（pg-problem-window 风格）
   - 实线边框 + 圆角 + 阴影
   ============================================ */

#page-camera {
  background: #F8F6F0;
}

/* --- 页面容器：与 P6 polya-guide-container 布局一致 --- */
.camera-container {
  width: 100%;
  height: 100vh;
  padding: calc(var(--topbar-height) + 1.5rem) 1.5rem 2rem;
  padding-left: 17.5rem;
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  max-width: var(--content-max-w);
  margin: 0 auto;
  overflow-x: hidden;
  overflow-y: auto;
  scrollbar-width: thin;
}
.camera-container::-webkit-scrollbar { width: 5px; }
.camera-container::-webkit-scrollbar-track { background: transparent; }
.camera-container::-webkit-scrollbar-thumb { background: rgba(255,193,7,0.3); border-radius: 4px; }

/* =============================================
   上传卡片窗口：科技玻璃拟态
   ============================================= */
.camera-upload-card {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-xl);
  padding: 0;
  width: 100%;
  flex-shrink: 0;
  position: relative;
  overflow: hidden;
  box-shadow: var(--glass-shadow), var(--glass-inset);
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

/* ★ 卡片顶部高光 */
.camera-upload-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 50%;
  background: linear-gradient(to bottom, rgba(255,255,255,0.15), transparent);
  pointer-events: none;
}

.camera-upload-card:hover {
  border-color: rgba(91,141,239,0.4);
  box-shadow:
    0 12px 40px rgba(91,141,239,0.18),
    0 4px 16px rgba(0,0,0,0.06),
    inset 0 1px 0 rgba(255,255,255,0.9);
  transform: translateY(-4px) scale(1.01);   /* ★ 微微放大 */
}

.camera-upload-card.has-image {
  border-color: rgba(76,217,100,0.5);
}

/* --- 卡片头部：科技渐变 --- */
.camera-upload-header {
  display: flex;
  align-items: center;
  gap: 12px;                   /* ★ 增大间距 */
  padding: 16px 26px;          /* ★ 增大内边距 */
  border-bottom: 1.5px solid rgba(91,141,239,0.15);
  background: linear-gradient(
    135deg,
    rgba(227,242,253,0.65) 0%,
    rgba(179,229,252,0.4) 100%
  );
}

.camera-upload-icon {
  font-size: 24px;              /* ★ 稍大 */
  filter: drop-shadow(0 2px 4px rgba(91,141,239,0.15));
}

.camera-upload-label {
  font-size: 16px;
  font-weight: 800;
  color: #DAA520;            /* ★ 金色 */
  text-transform: uppercase;
}

.camera-upload-hint {
  font-size: 13px;
  color: #666;               /* ★ 深灰黑 */
  margin-left: auto;
  letter-spacing: 1px;
}

/* --- 卡片内容区 --- */
.camera-upload-body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 240px;
  padding: 24px;
  background: #fafbff;
}

.upload-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  text-align: center;
  padding: 20px 0;
}
.upload-placeholder.hidden { display: none !important; }

.upload-icon {
  font-size: 52px;
  opacity: 0.65;
  transition: transform 0.3s ease;
}
.camera-upload-card:hover .upload-icon {
  transform: scale(1.15);
  opacity: 0.85;
}

.upload-text {
  font-size: 16px;
  font-weight: 600;
  color: #222;               /* ★ 黑色 */
  letter-spacing: 1px;
}

.upload-hint {
  font-size: 13px;
  color: #777;               /* ★ 深灰 */
}

/* --- 图片预览 --- */
.camera-preview-img {
  max-width: 100%;
  max-height: 320px;
  object-fit: contain;
  border-radius: 10px;
  box-shadow: 0 2px 16px rgba(0,0,0,0.08);
  display: block;
}

/* =============================================
   操作按钮行（仿 P6 输入区风格）
   ============================================= */
.camera-actions-row {
  display: flex;
  gap: 14px;
  justify-content: center;
  padding: 8px 0;
  flex-shrink: 0;
}

.camera-btn-submit,
.camera-btn-abort {
  padding: 0.75rem 2rem;
  font-size: 0.9375rem;
  font-weight: 700;
  min-height: var(--btn-height);
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.25s ease;
  letter-spacing: 0.0625rem;
  white-space: nowrap;
}

.camera-btn-submit {
  color: #fff;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  box-shadow: 0 4px 14px rgba(91,141,239,0.25), 0 1px 5px rgba(91,141,239,0.1);
}
.camera-btn-submit:hover:not(:disabled) {
  transform: translateY(-2px) scale(1.03);
  box-shadow: 0 6px 24px rgba(91,141,239,0.5);      /* ★ 主色阴影 */
}
.camera-btn-submit:disabled {
  opacity: 0.45;
  cursor: not-allowed;
  transform: none !important;
}

.camera-btn-abort {
  color: #fff;
  background: linear-gradient(135deg, #ef4444, #dc2626);
  box-shadow: 0 4px 16px rgba(239,68,68,0.30);
}
.camera-btn-abort:hover:not(:disabled) {
  transform: translateY(-2px) scale(1.03);
  box-shadow: 0 6px 24px rgba(239,68,68,0.45);
}
.camera-btn-abort:disabled {
  opacity: 0.32;
  cursor: not-allowed;
  transform: none !important;
  background: #ccc;
  box-shadow: none;
}

/* =============================================
   AI 分析状态区：科技玻璃拟态
   ============================================= */
.camera-status-area {
  animation: fadeInUp 0.4s ease both;
  flex-shrink: 0;
}

.camera-status-card {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid rgba(255,179,64,0.28);
  border-radius: var(--radius-xl);
  padding: 2rem 1.75rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  position: relative;
  overflow: hidden;
  box-shadow: var(--glass-shadow), var(--glass-inset);
}

/* ★ 状态卡内部微光动画 */
.camera-status-card::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: conic-gradient(
    from 0deg,
    transparent,
    rgba(255,193,7,0.04),
    transparent 30%
  );
  animation: statusCardGlow 6s linear infinite;
  pointer-events: none;
}
@keyframes statusCardGlow {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}

.camera-thinking-img {
  width: 64px;
  opacity: 0.85;
  animation: pg-thinking-bounce 1.4s ease-in-out infinite;
}

.camera-thinking-text {
  font-size: 0.9375rem;
  color: #f59e0b;
  font-weight: 600;
  letter-spacing: 0.125rem;
  animation: pg-thinking-pulse 1.6s ease-in-out infinite;
}

/* =============================================
   答案评价页面
   ============================================= */
.review-container {
  max-width: 680px;
  width: 100%;
  margin: 0 auto;
  padding: 3.5rem 1rem 5rem;
  height: 100%;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.review-card {
  background: rgba(255,255,255,0.9);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1.5px solid rgba(255,255,255,0.5);
  border-radius: var(--radius-lg);
  box-shadow: 0 4px 20px rgba(0,0,0,0.06);
  overflow: hidden;
}

.review-card-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.25rem;
  background: linear-gradient(135deg, rgba(99,102,241,0.06), rgba(41,182,246,0.04));
  border-bottom: 1px solid rgba(99,102,241,0.1);
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--color-primary);
}

.review-card-header svg {
  color: var(--color-primary);
}

.review-card-body {
  padding: 1rem 1.25rem;
  font-size: 0.95rem;
  line-height: 1.8;
  color: #1a1a1a;
}

/* ====== 作答图片区域（相对定位，用于叠加 loading）====== */
.review-image-body {
  position: relative;
  display: flex;
  justify-content: center;
  padding: 0.75rem;
}

.review-answer-img {
  max-width: 100%;
  max-height: 320px;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(0,0,0,0.08);
  object-fit: contain;
  background: #fafafa;
}

/* ★ Loading 叠加层：绝对定位在图片区域上方 */
.review-overlay-loading {
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  background: rgba(255,255,255,0.88);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  color: var(--color-primary);
  font-size: 0.9rem;
  font-weight: 500;
  z-index: 5;
  border-radius: var(--radius-sm);
  transition: opacity 0.3s ease;
}
.review-overlay-loading.hidden {
  display: none;
}

.review-loading-spinner {
  width: 36px;
  height: 36px;
  border: 3px solid rgba(99,102,241,0.15);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ★ 查看分析按钮区 */
.review-toggle-area {
  padding: 0 1.25rem 0.75rem;
}
.review-toggle-area.hidden {
  display: none;
}

.review-toggle-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  padding: 0.7rem 1.2rem;
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--color-primary);
  background: rgba(99,102,241,0.06);
  border: 1.5px dashed rgba(99,102,241,0.25);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.25s ease;
  letter-spacing: 0.3px;
}
.review-toggle-btn:hover {
  background: rgba(99,102,241,0.12);
  border-color: rgba(99,102,241,0.4);
}
.review-toggle-btn.active #review-toggle-icon {
  transform: rotate(180deg);
}

/* ★ 分析结果内容区（可展开/收起） */
.review-eval-result {
  padding: 0 1.25rem 1.25rem;
  overflow: hidden;
  transition: max-height 0.35s ease, opacity 0.3s ease, padding 0.3s ease;
}
.review-eval-result.hidden {
  display: none;
  max-height: 0;
  opacity: 0;
  padding: 0 1.25rem 0;
}
.review-eval-result.expanded {
  max-height: 800px;
  opacity: 1;
}

.review-eval-content {
  font-size: 0.9rem;
  line-height: 1.85;
  color: #333;
  white-space: pre-wrap;
  background: rgba(99,102,241,0.03);
  border: 1px solid rgba(99,102,241,0.08);
  border-radius: var(--radius-sm);
  padding: 1rem 1.2rem;
}

.review-actions {
  display: flex;
  justify-content: center;
  padding: 0.75rem 0;
}

.review-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0.8rem 2rem;
  font-size: 1rem;
  font-weight: 700;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.25s ease;
  letter-spacing: 0.5px;
}

.review-btn-analyze {
  color: #fff;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  box-shadow: 0 4px 16px rgba(91,141,239,0.35);
}
.review-btn-analyze:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(91,141,239,0.5);
}

.q-action-upload {
  color: #fff;
  background: linear-gradient(135deg, #6366F1, #8B5CF6);
  box-shadow: 0 2px 10px rgba(99,102,241,0.25);
}
.q-action-upload:hover {
  background: linear-gradient(135deg, #4F46E5, #7C3AED);
  transform: translateY(-2px);
}

/* ============================================
 *  ★ 左侧垂直悬浮导航栏
 *  智慧课堂风格：玻璃拟态竖排导航
 * ============================================ */
.bottom-nav {
  position: fixed;
  top: 50%;
  right: 1rem;
  transform: translateY(-50%);
  z-index: 998;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 0.5rem;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1.5px solid rgba(255, 255, 255, 0.65);
  border-radius: var(--radius-xl);
  box-shadow:
    0 8px 32px rgba(99, 102, 241, 0.12),
    0 2px 8px rgba(0, 0, 0, 0.04);
  transition: all 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

.bottom-nav:hover {
  box-shadow:
    0 12px 40px rgba(99, 102, 241, 0.18),
    0 4px 14px rgba(0, 0, 0, 0.06);
}

.bottom-nav-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 3.5rem;
  padding: 0.5rem 0.25rem;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.3s ease;
  background: transparent;
  border: none;
  color: var(--color-text-muted);
  font-size: 0.625rem;
  font-weight: 600;
  letter-spacing: 0.5px;
  gap: 0.25rem;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  text-align: center;
}

.bottom-nav-item .nav-icon {
  font-size: 1.375rem;
  line-height: 1;
  transition: all 0.3s ease;
}

.bottom-nav-item .nav-label {
  font-size: 0.625rem;
  letter-spacing: 0.5px;
  transition: all 0.3s ease;
}

.bottom-nav-item:hover {
  background: rgba(99, 102, 241, 0.08);
  color: var(--color-primary);
}

.bottom-nav-item.active {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: #fff;
  box-shadow: 0 3px 12px rgba(99, 102, 241, 0.3);
}

.bottom-nav-item.active .nav-icon {
  transform: scale(1.1);
}

/* ============================================
 *  ★ 顶部用户信息栏 + 模式切换
 *  智慧课堂风格：简洁玻璃拟态条
 * ============================================ */
.top-info-bar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 997;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-xl);
  height: var(--topbar-height);
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.4);
  box-shadow: 0 2px 8px rgba(99, 102, 241, 0.06);
  transition: all 0.3s ease;
}

.top-info-left {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.top-info-avatar {
  width: 1.75rem;
  height: 1.75rem;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.875rem;
  color: #fff;
  box-shadow: 0 2px 8px rgba(99, 102, 241, 0.2);
}

.top-info-name {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-text-primary);
  letter-spacing: 0.5px;
}

.top-info-right {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

/* ★ 顶部栏在欢迎页/过渡页隐藏 */
#page-welcome .top-info-bar,
#page-intro .top-info-bar {
  display: none;
}

/* ============================================
 *  ★ 响应式适配
 *  目标：2560x1600 (16:10) 高分平板 + 16:9 电脑
 * ============================================ */

/* —— 16:9 电脑屏幕（宽度 ≥ 1440px）—— */
@media (min-width: 1440px) {
  .main-menu {
    padding-left: var(--space-xl);
    padding-right: var(--space-xl);
  }
  .practice-container,
  .topic-detail-container {
    padding-left: var(--space-xl);
    padding-right: var(--space-xl);
  }
  .polya-guide-container,
  .camera-container {
    padding-left: 17.5rem;
  }
}

/* —— 大屏高分平板适配（≥ 1920px）—— */
@media (min-width: 1920px) {
  :root {
    --base-font-size: 17px;
  }
  .logo-img {
    width: 20rem;
  }
  .main-title {
    font-size: 4.5rem;
  }
}

/* —— 中等屏幕（1280px ~ 1439px）—— */
@media (max-width: 1439px) {
  .polya-guide-container,
  .camera-container {
    padding-left: 14rem;
  }
}

/* —— 小屏幕适配（≤ 1280px）—— */
@media (max-width: 1280px) {
  :root {
    --base-font-size: 15px;
  }
  .polya-guide-container,
  .camera-container {
    padding-left: 2rem;
  }
  .polya-avatar {
    display: none;
  }
  .main-menu {
    padding: 2rem 1.5rem 7.5rem;
  }
  .topic-list {
    grid-template-columns: repeat(2, 1fr) !important;
  }
}

/* —— 更小屏幕（≤ 1024px）—— */
@media (max-width: 1024px) {
  :root {
    --base-font-size: 14px;
  }
  .menu-top-row {
    flex-direction: column;
    gap: 1rem;
  }
  .menu-feature-card {
    width: 100% !important;
  }
  .method-steps {
    grid-template-columns: 1fr;
  }
}

/* ★ 右侧有导航栏时，页面左移留出空间 */
.page > .practice-container,
.page > .topic-detail-container,
.page > .polya-guide-container,
.page > .camera-container,
.page > .main-menu {
  padding-right: 5.5rem;
}

/* ============================================
 *  ★ 级联选择器样式
 *  学段 → 年级 → 知识点 → 难度/题量 → 生成
 * ============================================ */

.cascade-selector {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  width: 100%;
  align-items: center;
  margin: auto 0;
  animation: fadeInUp 0.45s ease both;
}
.cascade-selector.hidden { display: none; }

.cascade-step {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  width: 100%;
  max-width: 48rem;
  transition: all 0.4s ease;
  animation: cascadeSlideIn 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}
.cascade-step.hidden { display: none; }

@keyframes cascadeSlideIn {
  from { opacity: 0; transform: translateY(20px) scale(0.97); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}

/* ★ 步骤头部（含返回按钮） */
.cascade-step-header {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  position: relative;
  max-width: 500px;
  margin: 0 auto;
}

.cascade-back-btn {
  position: absolute;
  left: -60px;
  width: 2.5rem;
  height: 2.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-gold);
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: 50%;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: var(--glass-shadow);
  flex-shrink: 0;
}
.cascade-back-btn:hover {
  background: var(--glass-bg-hover);
  transform: translateX(-4px);
  border-color: var(--color-gold);
}

.cascade-step-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-gold);
  letter-spacing: 2px;
  text-align: center;
  margin: 0;
}

/* ★ 卡片网格 */
.cascade-grid {
  display: grid;
  grid-template-columns: repeat(3, 150px);
  gap: 2.5rem;
  width: 100%;
  justify-items: center;
  justify-content: center;
}
.cascade-grid-sm {
  grid-template-columns: repeat(3, 150px);
  gap: 2.5rem;
  justify-items: center;
  justify-content: center;
  max-width: 600px;
  margin: 0 auto;
}
/* 知识点区由手风琴接管，不再使用 cascade-grid-kp 网格 */
#cascade-step-points .cascade-grid-kp {
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
}

@media (max-width: 1024px) {
  .cascade-grid { grid-template-columns: repeat(2, 1fr); }
  .cascade-grid-sm { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 640px) {
  .cascade-grid { grid-template-columns: 1fr; }
  .cascade-grid-sm { grid-template-columns: repeat(2, 1fr); }
}

/* ★ 阶段/年级卡片 */
.cascade-card {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-lg);
  padding: 2rem 1.5rem;
  cursor: pointer;
  transition: all 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  position: relative;
  overflow: hidden;
  box-shadow: var(--glass-shadow), var(--glass-inset);
  user-select: none;
  min-width: 0;
}

.cascade-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 50%;
  background: linear-gradient(to bottom, rgba(255,255,255,0.18), transparent);
  pointer-events: none;
}

.cascade-card:hover {
  transform: translateY(-6px) scale(1.03);
  background: var(--glass-bg-hover);
  border-color: rgba(255, 193, 7, 0.4);
  box-shadow: var(--glass-shadow-hover), var(--glass-inset);
}

.cascade-card:active {
  transform: translateY(-2px) scale(0.98);
}

.cascade-card.selected {
  border-color: var(--color-gold);
  background: linear-gradient(135deg,
    rgba(255, 215, 0, 0.12) 0%,
    rgba(255, 255, 255, 0.75) 100%
  );
  box-shadow: 0 0 24px rgba(255, 193, 7, 0.18), var(--glass-inset);
}

.cascade-card-icon {
  font-size: 3rem;
  line-height: 1;
}

.cascade-card-name {
  font-size: 1.05rem;
  font-weight: 700;
  color: #222;
  letter-spacing: 0.5px;
}

.cascade-card-meta {
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

/* ★ 知识点卡片（多选） */
.cascade-kp-card {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-md);
  padding: 0.875rem 1rem;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  position: relative;
  overflow: hidden;
  box-shadow: var(--glass-shadow);
  user-select: none;
}

.cascade-kp-card:hover {
  border-color: rgba(99, 102, 241, 0.35);
  transform: translateX(4px);
}

.cascade-kp-card.checked {
  border-color: var(--color-gold);
  background: linear-gradient(135deg,
    rgba(255, 215, 0, 0.1) 0%,
    rgba(255, 255, 255, 0.7) 100%
  );
  box-shadow: 0 0 18px rgba(255, 193, 7, 0.12);
}

.cascade-kp-checkbox {
  width: 1.375rem;
  height: 1.375rem;
  min-width: 1.375rem;
  border-radius: 6px;
  border: 2px solid rgba(148, 163, 184, 0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  color: #fff;
  transition: all 0.25s ease;
}

.cascade-kp-card.checked .cascade-kp-checkbox {
  background: var(--color-gold);
  border-color: var(--color-gold);
}

.cascade-kp-name {
  flex: 1;
  font-size: 0.9rem;
  font-weight: 600;
  color: #222;
  letter-spacing: 0.3px;
}

.cascade-kp-type {
  font-size: 0.7rem;
  color: var(--color-text-muted);
  background: rgba(148, 163, 184, 0.1);
  padding: 0.2rem 0.6rem;
  border-radius: 10px;
  white-space: nowrap;
}

.cascade-kp-diff {
  display: flex;
  gap: 2px;
}
.cascade-kp-diff-dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: #ccc;
}
.cascade-kp-diff-dot.lit { background: var(--color-gold); }

/* ★ 配置区（难度 + 题量） */
.cascade-config {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 2.5rem;
  margin-top: 0.5rem;
}

.cascade-config-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.cc-label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  letter-spacing: 1px;
}

.cc-difficulty {
  display: flex;
  gap: 0;
  background: rgba(99, 102, 241, 0.08);
  border-radius: var(--radius-full);
  padding: 0.2rem;
}

.cc-diff-btn {
  padding: 0.45rem 1rem;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-text-muted);
  border: none;
  background: transparent;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all 0.25s ease;
}
.cc-diff-btn.active {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: #fff;
  box-shadow: 0 2px 8px rgba(99, 102, 241, 0.25);
}
.cc-diff-btn:hover:not(.active) {
  color: var(--color-primary);
}

.cc-count-stepper {
  display: flex;
  align-items: center;
  gap: 0;
  background: rgba(99, 102, 241, 0.08);
  border-radius: var(--radius-full);
  padding: 0.2rem;
}

.cc-count-btn {
  width: 2.2rem;
  height: 2.2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-primary);
  border: none;
  background: transparent;
  border-radius: 50%;
  cursor: pointer;
  transition: all 0.2s ease;
}
.cc-count-btn:hover {
  background: rgba(99, 102, 241, 0.15);
}

.cc-count-val {
  min-width: 2.2rem;
  text-align: center;
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--color-primary);
}

/* ★ 生成按钮 */
.cascade-generate-btn {
  margin: 0.5rem auto 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.625rem;
  padding: 0.875rem 3rem;
  font-size: 1.1rem;
  font-weight: 700;
  color: #fff;
  background: linear-gradient(135deg, var(--color-gold-light), var(--color-accent-warm));
  border: none;
  border-radius: var(--radius-full);
  cursor: pointer;
  letter-spacing: 2px;
  transition: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  box-shadow: 0 6px 24px rgba(255, 193, 7, 0.35), 0 2px 8px rgba(255, 159, 28, 0.15);
  min-width: 14rem;
}

.cascade-generate-btn:hover {
  transform: translateY(-4px) scale(1.05);
  box-shadow: 0 12px 36px rgba(255, 193, 7, 0.5), 0 4px 14px rgba(255, 159, 28, 0.25);
}

.cascade-generate-btn:active {
  transform: translateY(-1px) scale(0.98);
}

.cascade-generate-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

/* ============================================
 *  ★ 题目展示区
 * ============================================ */

.questions-display {
  animation: fadeInUp 0.5s ease both;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.questions-display.hidden { display: none; }

.qd-status-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-md);
  padding: 0.75rem 1.25rem;
  box-shadow: var(--glass-shadow);
}

.qd-status-info {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  font-weight: 600;
  letter-spacing: 0.5px;
  flex: 1;
}

.qd-status-actions {
  display: flex;
  gap: 0.625rem;
  align-items: center;
}

.qd-back-btn,
.qd-regenerate-btn {
  padding: 0.5rem 1.25rem;
  font-size: 0.85rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all 0.25s ease;
  letter-spacing: 1px;
  white-space: nowrap;
}

.qd-back-btn {
  color: var(--color-text-muted);
  background: rgba(148, 163, 184, 0.1);
  border: 1.5px solid rgba(148, 163, 184, 0.2);
}
.qd-back-btn:hover {
  background: rgba(148, 163, 184, 0.2);
  border-color: rgba(148, 163, 184, 0.4);
  transform: translateY(-1px);
}

.qd-regenerate-btn {
  color: var(--color-primary);
  background: rgba(99, 102, 241, 0.08);
  border: 1.5px solid rgba(99, 102, 241, 0.2);
}

.qd-regenerate-btn:hover {
  background: rgba(99, 102, 241, 0.15);
  border-color: var(--color-primary);
  transform: translateY(-1px);
}

/* ★ 题目列表 */
.q-list {
  display: flex;
  flex-direction: column;
  gap: 0.875rem;
}

.q-card {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem;
  transition: all 0.35s ease;
  cursor: pointer;
  box-shadow: var(--glass-shadow), var(--glass-inset);
  position: relative;
  overflow: hidden;
}

.q-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 50%;
  background: linear-gradient(to bottom, rgba(255,255,255,0.15), transparent);
  pointer-events: none;
}

.q-card:hover {
  border-color: rgba(255, 193, 7, 0.4);
  transform: translateX(6px);
  box-shadow: var(--glass-shadow-hover), var(--glass-inset);
}

.q-card-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.q-card-num {
  width: 1.75rem;
  height: 1.75rem;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: #fff;
  font-size: 0.8rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.q-card-meta {
  font-size: 0.75rem;
  color: #F59E0B;
  letter-spacing: 0.5px;
  font-weight: 600;
}

.q-card-body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
  font-size: 0.95rem;
  color: #1a1a1a;
  line-height: 1.75;
  margin-bottom: 0.75rem;
}

.q-card-actions {
  display: flex;
  gap: 0.625rem;
  justify-content: flex-end;
  padding-top: 0.75rem;
  border-top: 1px dashed rgba(99, 102, 241, 0.15);
}

.q-action-btn {
  padding: 0.5rem 1.25rem;
  font-size: 0.8rem;
  font-weight: 700;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.25s ease;
  letter-spacing: 0.5px;
}

.q-action-start {
  color: #fff;
  background: linear-gradient(135deg, #6366F1, #8B5CF6);
  border-radius: var(--radius-sm);
  box-shadow: 0 2px 10px rgba(99,102,241,0.25);
}
.q-action-start:hover { transform: translateY(-2px); box-shadow: 0 4px 16px rgba(99,102,241,0.4); }

.q-action-answer {
  color: #fff;
  background: linear-gradient(135deg, #6366F1, #8B5CF6);
  box-shadow: 0 2px 10px rgba(99,102,241,0.25);
}
.q-action-answer:hover {
  background: linear-gradient(135deg, #4F46E5, #7C3AED);
  transform: translateY(-1px);
}

.q-answer-panel {
  display: none;
  margin-top: 0.75rem;
  padding: 0.875rem 1rem;
  background: rgba(227, 242, 253, 0.6);
  border-left: 3px solid var(--color-primary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: 0.85rem;
  color: #1a1a1a;
  line-height: 1.8;
}
.q-answer-panel.show { display: block; animation: fadeInUp 0.3s ease both; }
.q-answer-panel .q-answer-label {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-gold);
  letter-spacing: 1px;
  margin-bottom: 0.5rem;
}

/* ============================================
 *  ★ 生成中加载态
 * ============================================ */

.cascade-loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 3rem 1rem;
  gap: 1.25rem;
  animation: fadeInUp 0.4s ease both;
}

.cascade-loading.hidden { display: none; }

.cascade-loading-img {
  width: 80px;
  height: auto;
  opacity: 0.85;
  animation: pg-thinking-bounce 1.4s ease-in-out infinite;
}

.cascade-loading-text {
  font-size: 1rem;
  color: var(--color-gold);
  font-weight: 600;
  letter-spacing: 1.5px;
  animation: pg-thinking-pulse 1.6s ease-in-out infinite;
}

/* ============================================
 *  ★ 手风琴式章节选择器样式
 *  章节卡片单列堆叠 → 展开后知识点 3 列矩阵
 * ============================================ */

/* 章节卡片 */
.cascade-chapter-card {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid var(--glass-border-subtle);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all 0.35s ease;
  box-shadow: var(--glass-shadow), var(--glass-inset);
}

.cascade-chapter-card.open {
  border-color: rgba(255, 193, 7, 0.4);
  box-shadow: var(--glass-shadow-hover), var(--glass-inset);
}

/* 章节头部（可点击展开/收起） */
.cascade-chapter-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.875rem 1.25rem;
  cursor: pointer;
  transition: all 0.25s ease;
  user-select: none;
  position: relative;
}

.cascade-chapter-header:hover {
  background: rgba(255, 193, 7, 0.06);
}

.cascade-chapter-header .chapter-arrow {
  font-size: 0.85rem;
  color: var(--color-gold);
  transition: transform 0.3s ease;
  flex-shrink: 0;
}

.cascade-chapter-card.open .cascade-chapter-header .chapter-arrow {
  transform: rotate(90deg);
}

.cascade-chapter-header .chapter-name {
  flex: 1;
  font-size: 0.95rem;
  font-weight: 700;
  color: #222;
  letter-spacing: 0.5px;
}

.cascade-chapter-header .chapter-count {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  background: rgba(148, 163, 184, 0.1);
  padding: 0.2rem 0.7rem;
  border-radius: 10px;
}

/* 章节内容区（知识点 3 列网格） */
.cascade-chapter-body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
  display: none;
  padding: 0 1.25rem 1rem;
  animation: chapterExpand 0.3s ease both;
}

.cascade-chapter-card.open .cascade-chapter-body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.625rem;
}

@keyframes chapterExpand {
  from { opacity: 0; transform: translateY(-4px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* 响应式：中等屏幕知识点2列 */
@media (max-width: 1200px) {
  .cascade-chapter-card.open .cascade-chapter-body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .cascade-chapter-card.open .cascade-chapter-body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
    grid-template-columns: 1fr;
  }
}

/* 知识点卡片（章节内部使用，单选模式） */
.cascade-chapter-kp {
  background: rgba(255, 255, 255, 0.4);
  border: 1.5px solid rgba(99, 102, 241, 0.12);
  border-radius: 10px;
  padding: 0.7rem 0.85rem;
  cursor: pointer;
  transition: all 0.25s ease;
  display: flex;
  align-items: center;
  gap: 0.55rem;
  position: relative;
  overflow: hidden;
  user-select: none;
}

.cascade-chapter-kp:hover {
  border-color: rgba(99, 102, 241, 0.35);
  background: rgba(99, 102, 241, 0.06);
  transform: translateX(3px);
}

.cascade-chapter-kp.selected {
  border-color: var(--color-gold);
  background: linear-gradient(135deg,
    rgba(255, 215, 0, 0.12) 0%,
    rgba(255, 255, 255, 0.6) 100%
  );
  box-shadow: 0 0 14px rgba(255, 193, 7, 0.12);
}

.cascade-chapter-kp .kp-radio {
  width: 1.2rem;
  height: 1.2rem;
  min-width: 1.2rem;
  border-radius: 50%;
  border: 2px solid rgba(148, 163, 184, 0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.25s ease;
  flex-shrink: 0;
}

.cascade-chapter-kp.selected .kp-radio {
  border-color: var(--color-gold);
  background: var(--color-gold);
}

.cascade-chapter-kp.selected .kp-radio::after {
  content: '';
  width: 0.4rem;
  height: 0.4rem;
  border-radius: 50%;
  background: #fff;
}

.cascade-chapter-kp .kp-name {
  flex: 1;
  font-size: 0.85rem;
  font-weight: 600;
  color: #222;
  letter-spacing: 0.3px;
  line-height: 1.3;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.cascade-chapter-kp .kp-type {
  font-size: 0.65rem;
  color: var(--color-text-muted);
  background: rgba(148, 163, 184, 0.1);
  padding: 0.15rem 0.5rem;
  border-radius: 8px;
  white-space: nowrap;
  flex-shrink: 0;
}

/* ============================================
 *  ★ 闪卡游戏样式（生成题目期间的互动游戏）
 * ============================================ */

/* 闪卡游戏容器 */
.flashcard-game {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2rem;
  width: 100%;
  max-width: 42rem;
  margin: auto;
  padding: 1.5rem 1rem 3rem;
  animation: fadeInUp 0.45s ease both;
}

.flashcard-game.hidden { display: none; }

/* 闪卡头部：头像 + 文字 */
.flashcard-header {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  padding: 0.5rem 0;
}

.flashcard-avatar {
  width: 72px;
  height: auto;
  animation: flashcardAvatarFloat 2.5s ease-in-out infinite;
  filter: drop-shadow(0 4px 12px rgba(99, 102, 241, 0.25));
}

@keyframes flashcardAvatarFloat {
  0%, 100% { transform: translateY(0) rotate(-3deg); }
  25%  { transform: translateY(-8px) rotate(0deg); }
  50%  { transform: translateY(-2px) rotate(3deg); }
  75%  { transform: translateY(-10px) rotate(-1deg); }
}

.flashcard-loading-text-wrap {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.flashcard-loading-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-gold);
  letter-spacing: 1.5px;
}

/* 加载点动画（始终循环） */
.flashcard-loading-dots {
  display: inline-flex;
  gap: 2px;
  margin-left: 4px;
}

.flashcard-loading-dots span {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--color-gold);
  animation: flashcardDotsBounce 1.2s ease-in-out infinite;
}

.flashcard-loading-dots span:nth-child(1) { animation-delay: 0s; }
.flashcard-loading-dots span:nth-child(2) { animation-delay: 0.2s; }
.flashcard-loading-dots span:nth-child(3) { animation-delay: 0.4s; }

@keyframes flashcardDotsBounce {
  0%, 80%, 100% { transform: translateY(0); opacity: 0.3; }
  40% { transform: translateY(-6px); opacity: 1; }
}

/* 闪卡题目框 */
/* ===== 故事卡片（替代原问答选项）===== */
.flashcard-story-box {
  width: 100%;
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1.5px solid rgba(255, 215, 0, 0.2);
  border-radius: var(--radius-xl);
  padding: 1.75rem 2rem;
  box-shadow: var(--glass-shadow), var(--glass-inset);
  transition: all 0.35s ease;
  overflow: visible;
  animation: storyFadeIn 0.5s ease both;
  min-height: 10rem;
}

@keyframes storyFadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}

.flashcard-story-title {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--color-gold);
  text-align: center;
  margin: 0 0 1rem 0;
  letter-spacing: 1px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

.flashcard-story-title::before {
  content: '📖';
  font-size: 1.4rem;
}

.flashcard-story-body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
  font-size: 1.05rem;
  color: #2d2d2d;
  line-height: 2;
  text-align: left;
  letter-spacing: 0.3px;
}

/* ===== 进度条 ===== */
.flashcard-story-timer {
  display: flex;
  align-items: center;
  margin-top: 0.75rem;
}

.story-progress-track {
  flex: 1;
  height: 5px;
  background: rgba(148, 163, 184, 0.15);
  border-radius: 10px;
  overflow: hidden;
}

.story-progress-fill {
  height: 100%;
  width: 100%;
  background: linear-gradient(90deg, var(--color-gold-light), var(--color-gold));
  border-radius: 10px;
  transition: none;
}

.story-timer-text {
  display: none;
}

/* ===== 概念二选一卡片 ===== */
.flashcard-quiz-box {
  background: linear-gradient(135deg, #f0f4ff, #ede9fe);
  border-radius: 16px;
  padding: 1.25rem 1.5rem;
  margin: 0.75rem 0;
  border: 1.5px solid rgba(99, 102, 241, 0.15);
  position: relative;
}
.flashcard-quiz-box.hidden { display: none; }

.flashcard-quiz-badge {
  display: inline-block;
  background: linear-gradient(135deg, #6366f1, #8b5cf6);
  color: #fff;
  font-size: 0.7rem;
  font-weight: 700;
  padding: 0.2rem 0.65rem;
  border-radius: 99px;
  margin-bottom: 0.75rem;
  letter-spacing: 0.5px;
}

.flashcard-quiz-question {
  font-size: 0.95rem;
  font-weight: 600;
  color: #1e293b;
  line-height: 1.5;
  margin: 0 0 1rem 0;
}

.flashcard-quiz-options {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.flashcard-quiz-opt {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.7rem 1rem;
  border-radius: 12px;
  border: 2px solid #e2e8f0;
  background: #fff;
  cursor: pointer;
  transition: all 0.2s ease;
  text-align: left;
  font-size: 0.875rem;
  color: #334155;
}
.flashcard-quiz-opt:hover {
  border-color: #6366f1;
  background: #f5f3ff;
  transform: translateX(4px);
}
.flashcard-quiz-opt.correct {
  border-color: #22c55e;
  background: #f0fdf4;
  color: #166534;
}
.flashcard-quiz-opt.wrong {
  border-color: #ef4444;
  background: #fef2f2;
  color: #991b1b;
}
.flashcard-quiz-opt.disabled {
  pointer-events: none;
  opacity: 0.7;
}

.quiz-opt-label {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: #e0e7ff;
  color: #4f46e5;
  font-weight: 700;
  font-size: 0.8rem;
  flex-shrink: 0;
}
.flashcard-quiz-opt.correct .quiz-opt-label {
  background: #bbf7d0;
  color: #166534;
}
.flashcard-quiz-opt.wrong .quiz-opt-label {
  background: #fecaca;
  color: #991b1b;
}

.quiz-opt-text {
  flex: 1;
  line-height: 1.4;
}

.flashcard-quiz-feedback {
  margin-top: 0.75rem;
  padding: 0.6rem 0.85rem;
  border-radius: 10px;
  font-size: 0.8rem;
  line-height: 1.5;
  font-weight: 500;
}
.flashcard-quiz-feedback.hidden { display: none; }
.flashcard-quiz-feedback.correct {
  background: #f0fdf4;
  color: #166534;
  border: 1px solid #bbf7d0;
}
.flashcard-quiz-feedback.wrong {
  background: #fef2f2;
  color: #991b1b;
  border: 1px solid #fecaca;
}

/* 进度文字（已隐藏） */
.flashcard-progress {
  visibility: hidden;
  opacity: 0;
  height: 0;
  margin: 0;
  padding: 0;
  overflow: hidden;
  pointer-events: none;
}

/* 完成按钮 */
.flashcard-done-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.625rem;
  padding: 1rem 2.5rem;
  font-size: 1.15rem;
  font-weight: 700;
  color: #fff;
  background: linear-gradient(135deg, var(--color-gold-light), var(--color-accent-warm));
  border: none;
  border-radius: var(--radius-full);
  cursor: pointer;
  letter-spacing: 1.5px;
  transition: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  box-shadow: 0 6px 24px rgba(255, 193, 7, 0.35), 0 2px 8px rgba(255, 159, 28, 0.15);
  animation: fadeInUp 0.5s ease both;
}

.flashcard-done-btn:hover {
  transform: translateY(-3px) scale(1.04);
  box-shadow: 0 12px 36px rgba(255, 193, 7, 0.5), 0 4px 14px rgba(255, 159, 28, 0.25);
}

.flashcard-done-btn:active {
  transform: translateY(-1px) scale(0.98);
}

.flashcard-done-btn.hidden { display: none; }

/* 取消生成按钮 */
.flashcard-cancel-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  margin-top: 1rem;
  padding: 0.7rem 2rem;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-text-muted, #94a3b8);
  background: transparent;
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: var(--radius-full);
  cursor: pointer;
  letter-spacing: 0.5px;
  transition: all 0.3s ease;
}

.flashcard-cancel-btn:hover {
  color: #ef4444;
  border-color: rgba(239,68,68,0.4);
  background: rgba(239,68,68,0.06);
}

.flashcard-cancel-btn:active {
  transform: scale(0.97);
}

/* 响应式 */
@media (max-width: 768px) {
  .flashcard-story-box {
    padding: 1.25rem 1.25rem;
  }
  .flashcard-story-title {
    font-size: 1.05rem;
  }
  .flashcard-story-body {
  background: linear-gradient(135deg, #F8F6F0 0%, #F0EDE4 40%, #EBE7DC 100%);
    font-size: 0.95rem;
    line-height: 1.8;
  }
}