/* ================================================================
   基金从业学习平台 v3 — 现代玻璃态暗色主题
   设计参考: 2025-2026 知识付费 + Duolingo + Linear/Vercel 风格
   ================================================================ */

/* ============================================================
   设计令牌
   ============================================================ */
:root {
  /* 背景层级 */
  --bg-base: #09090f;
  --bg-surface: #12121a;
  --bg-glass: rgba(255,255,255,0.03);
  --bg-glass-hover: rgba(255,255,255,0.06);
  --bg-glass-strong: rgba(255,255,255,0.08);
  --bg-input: rgba(255,255,255,0.05);

  /* 文字 */
  --text: #e8e8ed;
  --text-secondary: #a0a0b0;
  --text-dim: #8b8b9e;
  --text-muted: #5c5c6e;

  /* 主色调 — indigo→violet */
  --primary: #6366f1;
  --primary-light: #818cf8;
  --primary-dark: #4f46e5;
  --primary-glow: rgba(99,102,241,0.25);
  --primary-glass: rgba(99,102,241,0.08);

  /* 功能色 */
  --success: #10b981;
  --success-glow: rgba(16,185,129,0.2);
  --success-glass: rgba(16,185,129,0.08);
  --danger: #ef4444;
  --danger-glow: rgba(239,68,68,0.2);
  --danger-glass: rgba(239,68,68,0.08);
  --gold: #f59e0b;
  --gold-glow: rgba(245,158,11,0.2);
  --gold-glass: rgba(245,158,11,0.08);

  /* 圆角 */
  --radius-xs: 6px;
  --radius-sm: 10px;
  --radius: 14px;
  --radius-lg: 18px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* 阴影 */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
  --shadow: 0 4px 12px rgba(0,0,0,0.4);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.5);
  --shadow-glow: 0 0 20px var(--primary-glow);
  --shadow-success: 0 0 20px var(--success-glow);

  /* 字体 */
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Cascadia Code", monospace;

  /* 过渡 */
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --transition-fast: 150ms var(--ease);
  --transition: 250ms var(--ease);
  --transition-slow: 400ms var(--ease);
}

/* ============================================================
   基础重置
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body {
  font-family: var(--font);
  background: var(--bg-base);
  color: var(--text);
  line-height: 1.7;
  min-height: 100dvh;
  overflow-x: hidden;
}

/* 微妙背景纹理 */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 50% -20%, rgba(99,102,241,0.06), transparent),
    radial-gradient(ellipse 60% 50% at 80% 80%, rgba(139,92,246,0.04), transparent);
  pointer-events: none;
  z-index: 0;
}

.hidden { display: none !important; }

/* 滚动条 */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.08); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: rgba(255,255,255,0.14); }

/* 文字选中 */
::selection { background: rgba(99,102,241,0.3); color: #fff; }

/* ============================================================
   排版工具
   ============================================================ */
.section-title {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin: 24px 0 12px;
  padding: 0 4px;
}

.empty {
  text-align: center;
  padding: 48px 24px;
  color: var(--text-dim);
  font-size: 14px;
}

/* ============================================================
   按钮系统
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 10px 20px;
  border: none;
  border-radius: var(--radius-full);
  cursor: pointer;
  font-size: 14px;
  font-weight: 600;
  font-family: var(--font);
  letter-spacing: 0.01em;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
  white-space: nowrap;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

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

/* 主要按钮 — 渐变 */
.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, #7c3aed 100%);
  color: #fff;
  box-shadow: 0 2px 8px var(--primary-glow);
}
.btn-primary:hover {
  box-shadow: 0 4px 16px var(--primary-glow), 0 0 0 1px rgba(99,102,241,0.3);
  transform: translateY(-1px);
}
.btn-primary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

/* 成功按钮 */
.btn-success {
  background: linear-gradient(135deg, var(--success) 0%, #059669 100%);
  color: #fff;
  box-shadow: 0 2px 8px var(--success-glow);
}
.btn-success:hover {
  box-shadow: 0 4px 16px var(--success-glow);
  transform: translateY(-1px);
}

/* 危险按钮 */
.btn-danger {
  background: linear-gradient(135deg, var(--danger) 0%, #dc2626 100%);
  color: #fff;
  box-shadow: 0 2px 8px var(--danger-glow);
}
.btn-danger:hover {
  box-shadow: 0 4px 16px var(--danger-glow);
  transform: translateY(-1px);
}

/* 轮廓按钮 */
.btn-outline {
  background: transparent;
  border: 1px solid rgba(255,255,255,0.1);
  color: var(--text-secondary);
}
.btn-outline:hover {
  border-color: rgba(255,255,255,0.2);
  color: var(--text);
  background: var(--bg-glass);
}

/* 文字按钮 */
.btn-text {
  background: none;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  font-family: var(--font);
}
.btn-text:hover {
  color: var(--text);
  background: var(--bg-glass);
}

/* 尺寸变体 */
.btn-full { width: 100%; }
.btn-sm { padding: 6px 14px; font-size: 12px; border-radius: var(--radius-full); }
.btn-lg { padding: 14px 28px; font-size: 16px; }

/* 图标按钮 */
.btn-icon {
  width: 40px; height: 40px; padding: 0;
  border-radius: 50%;
  font-size: 18px;
}

/* ============================================================
   表单
   ============================================================ */
.input {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--radius);
  background: var(--bg-input);
  color: var(--text);
  font-size: 14px;
  font-family: var(--font);
  transition: all var(--transition-fast);
  outline: none;
}
.input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-glow);
  background: rgba(255,255,255,0.07);
}
.input::placeholder { color: var(--text-muted); }

textarea.input { resize: vertical; min-height: 80px; }

select.input {
  appearance: none;
  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='%238b8b9e' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  padding-right: 36px;
  cursor: pointer;
}

.form-group { margin-bottom: 14px; }
.form-group label {
  display: block;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-dim);
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.form-row { display: flex; gap: 12px; }
.form-row .form-group { flex: 1; }

/* ============================================================
   顶部栏 — 玻璃模糊
   ============================================================ */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  background: rgba(18,18,26,0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(255,255,255,0.05);
  position: sticky;
  top: 0;
  z-index: 50;
}
.topbar-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.01em;
}
.topbar-info {
  font-size: 13px;
  color: var(--text-dim);
  font-variant-numeric: tabular-nums;
}

/* ============================================================
   底部导航 — 悬浮胶囊
   ============================================================ */
.bottom-nav {
  display: flex;
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  width: calc(100% - 32px);
  max-width: 440px;
  background: rgba(22,22,34,0.85);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--radius-xl);
  padding: 6px;
  z-index: 50;
  box-shadow: 0 8px 32px rgba(0,0,0,0.5), 0 0 0 1px rgba(255,255,255,0.03);
}
.nav-item {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 10px 8px;
  font-size: 12px;
  font-weight: 500;
  color: var(--text-dim);
  cursor: pointer;
  border-radius: var(--radius-lg);
  transition: all var(--transition);
  position: relative;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}
.nav-item.active {
  color: var(--text);
  font-weight: 700;
  background: var(--bg-glass-strong);
}
.nav-item.active::after {
  content: '';
  position: absolute;
  bottom: 4px;
  left: 50%;
  transform: translateX(-50%);
  width: 16px;
  height: 3px;
  background: var(--primary);
  border-radius: 2px;
}
.nav-item:active { transform: scale(0.95); }

/* ============================================================
   内容区
   ============================================================ */
.content {
  padding: 20px 16px;
  padding-bottom: 120px;
  max-width: 720px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
  animation: fadeInUp 0.35s var(--ease);
}

/* ============================================================
   登录页
   ============================================================ */
.login-container {
  max-width: 380px;
  margin: 80px auto 0;
  padding: 40px 32px;
  text-align: center;
  background: var(--bg-glass);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid rgba(255,255,255,0.06);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
}

.login-logo {
  font-size: 56px;
  margin-bottom: 8px;
  display: inline-block;
  width: 80px; height: 80px;
  line-height: 80px;
  border-radius: 50%;
  background: var(--primary-glass);
  box-shadow: 0 0 40px var(--primary-glow);
  animation: logoPulse 3s var(--ease) infinite;
}
@keyframes logoPulse {
  0%, 100% { box-shadow: 0 0 40px var(--primary-glow); }
  50% { box-shadow: 0 0 60px rgba(99,102,241,0.4); }
}

.login-container h2 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 4px;
  letter-spacing: -0.02em;
}
.login-sub {
  color: var(--text-dim);
  font-size: 13px;
  margin-bottom: 28px;
}

.login-form {
  display: flex;
  flex-direction: column;
  gap: 14px;
}
.login-form .input {
  text-align: center;
  font-size: 16px;
  letter-spacing: 0.2em;
  padding: 14px 16px;
}

.login-msg {
  font-size: 13px;
  color: var(--danger);
  margin-top: 12px;
  min-height: 20px;
}

/* ============================================================
   统计卡片 — Bento 网格
   ============================================================ */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin-bottom: 8px;
}

.stat-card {
  background: var(--bg-glass);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,0.05);
  border-radius: var(--radius);
  padding: 18px 16px;
  text-align: center;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}
.stat-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.08), transparent);
}
.stat-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
  border-color: rgba(255,255,255,0.08);
}

.stat-value {
  font-size: 32px;
  font-weight: 800;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  background: linear-gradient(135deg, var(--text) 0%, var(--primary-light) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.stat-card:nth-child(2) .stat-value {
  background: linear-gradient(135deg, var(--success) 0%, #34d399 100%);
  -webkit-background-clip: text;
  background-clip: text;
}
.stat-card:nth-child(3) .stat-value {
  background: linear-gradient(135deg, var(--primary-light) 0%, #a78bfa 100%);
  -webkit-background-clip: text;
  background-clip: text;
}
.stat-card:nth-child(4) .stat-value {
  background: linear-gradient(135deg, var(--danger) 0%, #f87171 100%);
  -webkit-background-clip: text;
  background-clip: text;
}

.stat-label {
  font-size: 11px;
  font-weight: 500;
  color: var(--text-dim);
  margin-top: 6px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ============================================================
   科目卡片
   ============================================================ */
.subject-card {
  background: var(--bg-glass);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,0.05);
  border-radius: var(--radius);
  padding: 18px;
  margin-bottom: 10px;
  cursor: pointer;
  transition: all var(--transition);
  position: relative;
  border-left: 3px solid var(--primary);
}
.subject-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
  border-left-color: var(--primary-light);
  background: var(--bg-glass-hover);
}
.subject-card:nth-child(2) { border-left-color: var(--success); }
.subject-card:nth-child(2):hover { border-left-color: #34d399; }
.subject-card:nth-child(3) { border-left-color: var(--gold); }
.subject-card:nth-child(3):hover { border-left-color: #fbbf24; }

.sc-header {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 10px;
  letter-spacing: -0.01em;
}

.sc-stats {
  display: flex;
  gap: 16px;
  font-size: 12px;
  color: var(--text-dim);
  margin-bottom: 10px;
  font-variant-numeric: tabular-nums;
}

.sc-bar {
  height: 6px;
  background: rgba(255,255,255,0.06);
  border-radius: 3px;
  overflow: hidden;
}
.sc-bar-fill {
  height: 100%;
  border-radius: 3px;
  background: linear-gradient(90deg, var(--primary), var(--primary-light));
  box-shadow: 0 0 8px var(--primary-glow);
  transition: width 0.8s var(--ease-spring);
  position: relative;
}
.sc-bar-fill::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
  animation: shimmer 2s ease-in-out infinite;
}
@keyframes shimmer {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

/* ============================================================
   章节列表
   ============================================================ */
.chapter-item {
  background: var(--bg-glass);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,0.05);
  border-radius: var(--radius);
  padding: 16px;
  margin-bottom: 8px;
  transition: all var(--transition);
}
.chapter-item:hover { border-color: rgba(255,255,255,0.1); }

.ci-info { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
.ci-no {
  font-size: 11px;
  font-weight: 600;
  color: var(--primary-light);
  background: var(--primary-glass);
  padding: 3px 8px;
  border-radius: var(--radius-xs);
  flex-shrink: 0;
}
.ci-title { font-size: 15px; font-weight: 600; }

.ci-meta {
  font-size: 12px;
  color: var(--text-dim);
  margin-bottom: 10px;
  display: flex;
  gap: 14px;
}

.ci-actions { display: flex; gap: 8px; flex-wrap: wrap; }

.exam-entry { margin-bottom: 16px; }

/* ============================================================
   章节目录树
   ============================================================ */
.toc-chapter {
  margin-bottom: 8px;
  border-radius: var(--radius);
  overflow: hidden;
  transition: all var(--transition);
}

.toc-ch-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px;
  background: var(--bg-glass);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,0.04);
  border-radius: var(--radius);
  cursor: pointer;
  transition: all var(--transition);
  user-select: none;
}
.toc-ch-header:hover {
  background: var(--bg-glass-hover);
  border-color: rgba(255,255,255,0.08);
}

.toc-ch-header .ch-label {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 15px;
  font-weight: 600;
  flex: 1;
}
.toc-ch-header .ch-no {
  font-size: 11px;
  font-weight: 700;
  color: var(--primary-light);
  background: var(--primary-glass);
  padding: 3px 8px;
  border-radius: var(--radius-xs);
  flex-shrink: 0;
}

.toc-ch-arrow {
  font-size: 12px;
  color: var(--text-dim);
  transition: transform 0.3s var(--ease);
  display: inline-block;
}
.toc-ch-arrow.open { transform: rotate(90deg); }

.toc-ch-header .ch-badge {
  font-size: 11px;
  font-weight: 600;
  color: var(--success);
  background: var(--success-glass);
  padding: 3px 10px;
  border-radius: var(--radius-full);
}

.toc-sections {
  padding: 6px 0;
  background: rgba(0,0,0,0.15);
  border-radius: 0 0 var(--radius) var(--radius);
}

.toc-section-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px 12px 24px;
  cursor: pointer;
  transition: all var(--transition-fast);
  border-left: 2px solid transparent;
  position: relative;
}
.toc-section-item:hover {
  background: var(--bg-glass-hover);
  border-left-color: rgba(255,255,255,0.1);
}
.toc-section-item.done {
  border-left-color: var(--success);
  background: var(--success-glass);
}

.toc-section-item .sec-dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: rgba(255,255,255,0.1);
  flex-shrink: 0;
  border: 2px solid var(--text-muted);
  transition: all var(--transition);
}
.toc-section-item.done .sec-dot {
  background: var(--success);
  border-color: var(--success);
  box-shadow: 0 0 8px var(--success-glow);
}

.toc-section-item .sec-number {
  font-size: 11px;
  color: var(--text-dim);
  flex-shrink: 0;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
}
.toc-section-item .sec-title { font-size: 14px; flex: 1; font-weight: 500; }

.toc-section-item .sec-ex-count {
  font-size: 11px;
  color: var(--text-dim);
  background: rgba(255,255,255,0.05);
  padding: 2px 8px;
  border-radius: var(--radius-xs);
}

.toc-ch-test {
  display: block;
  width: calc(100% - 8px);
  margin: 6px 4px 10px;
  padding: 12px;
  background: linear-gradient(135deg, var(--success), #059669);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 14px;
  font-weight: 600;
  font-family: var(--font);
  transition: all var(--transition);
  box-shadow: 0 2px 8px var(--success-glow);
}
.toc-ch-test:hover {
  box-shadow: 0 4px 16px var(--success-glow);
  transform: translateY(-1px);
}
.toc-ch-test:disabled {
  background: rgba(255,255,255,0.05);
  color: var(--text-muted);
  cursor: default;
  box-shadow: none;
  transform: none;
}

/* ============================================================
   面包屑
   ============================================================ */
.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  padding: 10px 4px;
  margin-bottom: 16px;
  font-size: 12px;
  color: var(--text-dim);
}
.breadcrumb span { white-space: nowrap; color: var(--text-muted); }
.breadcrumb a {
  color: var(--primary-light);
  text-decoration: none;
  cursor: pointer;
  font-weight: 500;
  transition: color var(--transition-fast);
}
.breadcrumb a:hover { color: var(--text); }

/* ============================================================
   内容阅读器
   ============================================================ */
.section-content {
  background: var(--bg-glass);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,0.05);
  border-radius: var(--radius);
  padding: 24px 20px;
  line-height: 1.9;
  font-size: 15px;
}

.section-content h3 {
  font-size: 19px;
  font-weight: 700;
  margin: 28px 0 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(255,255,255,0.06);
  letter-spacing: -0.01em;
}
.section-content h3:first-child { margin-top: 0; }

.section-content h4 {
  font-size: 16px;
  font-weight: 600;
  margin: 20px 0 10px;
  color: var(--text);
}

.section-content p {
  margin-bottom: 12px;
  color: #c8c8d4;
}
.section-content strong { color: #fff; font-weight: 600; }

.section-content ul, .section-content ol {
  margin: 10px 0 18px 22px;
  color: #c8c8d4;
}
.section-content li { margin-bottom: 8px; }

.section-content table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin: 16px 0;
  font-size: 13px;
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 1px solid rgba(255,255,255,0.06);
}
.section-content th {
  padding: 10px 12px;
  background: var(--bg-glass-strong);
  font-weight: 600;
  color: #fff;
  font-size: 12px;
  text-align: left;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}
.section-content td {
  padding: 10px 12px;
  border-top: 1px solid rgba(255,255,255,0.04);
  color: #c8c8d4;
}
.section-content tr:nth-child(even) td { background: rgba(255,255,255,0.015); }

/* ============================================================
   例题卡片
   ============================================================ */
.lesson-example {
  background: var(--primary-glass);
  border: 1px solid rgba(99,102,241,0.15);
  border-radius: var(--radius);
  padding: 16px;
  margin: 18px 0;
  position: relative;
}
.lesson-example::before {
  content: '经典例题';
  position: absolute;
  top: -10px;
  left: 16px;
  font-size: 11px;
  font-weight: 700;
  color: var(--primary-light);
  background: var(--bg-surface);
  padding: 2px 10px;
  border-radius: var(--radius-xs);
  letter-spacing: 0.03em;
}

.example-question {
  font-size: 14px;
  color: var(--text);
  margin: 6px 0 12px;
  line-height: 1.8;
  padding-right: 100px;
}

.example-toggle-btn {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 7px 16px;
  background: var(--primary-glass);
  color: var(--primary-light);
  border: 1px solid rgba(99,102,241,0.2);
  border-radius: var(--radius-full);
  cursor: pointer;
  font-size: 12px;
  font-weight: 600;
  transition: all var(--transition-fast);
  font-family: var(--font);
  margin-top: 4px;
}
.example-toggle-btn:hover {
  background: rgba(99,102,241,0.15);
  border-color: rgba(99,102,241,0.35);
}

.example-solution {
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px dashed rgba(99,102,241,0.15);
  font-size: 13px;
  color: #c8c8d4;
  line-height: 1.8;
}
.example-solution strong { color: var(--success); }
.example-solution.hidden { display: none; }

/* ============================================================
   关键知识点框
   ============================================================ */
.key-point {
  background: var(--gold-glass);
  border: 1px solid rgba(245,158,11,0.15);
  border-radius: var(--radius);
  padding: 16px;
  margin: 18px 0;
  position: relative;
}
.key-point::before {
  content: '📌 本节要点';
  position: absolute;
  top: -10px;
  left: 16px;
  font-size: 11px;
  font-weight: 700;
  color: var(--gold);
  background: var(--bg-surface);
  padding: 2px 10px;
  border-radius: var(--radius-xs);
  letter-spacing: 0.03em;
}
.key-point h4 { margin: 4px 0 10px; color: var(--gold); font-size: 14px; }
.key-point ul { margin: 0 0 0 18px; color: #c8c8d4; font-size: 13px; }
.key-point li { margin-bottom: 6px; }
.key-point strong { color: var(--gold); }

/* ============================================================
   节导航
   ============================================================ */
.section-nav {
  display: flex;
  gap: 10px;
  margin-top: 18px;
}
.section-nav .btn { flex: 1; }

/* ============================================================
   课后习题面板
   ============================================================ */
.section-exercise-panel {
  background: var(--bg-glass);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,0.05);
  border-radius: var(--radius);
  padding: 20px;
  margin-top: 18px;
}

.sep-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 18px;
}
.sep-header h4 { font-size: 16px; font-weight: 700; color: var(--text); }
.sep-header .sep-count {
  font-size: 12px;
  color: var(--text-dim);
  background: var(--bg-glass-strong);
  padding: 3px 10px;
  border-radius: var(--radius-full);
}

.exercise-item {
  background: rgba(255,255,255,0.02);
  border: 1px solid rgba(255,255,255,0.04);
  border-radius: var(--radius);
  padding: 16px;
  margin-bottom: 10px;
  transition: all var(--transition);
}
.exercise-item:hover { border-color: rgba(255,255,255,0.08); }

.exercise-item .ei-question {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text);
  line-height: 1.7;
}

.exercise-item .ei-options {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.exercise-item .ei-opt {
  padding: 8px 16px;
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.06);
  border-radius: var(--radius-full);
  cursor: pointer;
  font-size: 13px;
  transition: all var(--transition-fast);
  color: var(--text-secondary);
  user-select: none;
}
.exercise-item .ei-opt:hover {
  border-color: rgba(255,255,255,0.15);
  background: rgba(255,255,255,0.06);
}
.exercise-item .ei-opt.selected {
  border-color: var(--primary);
  background: var(--primary-glass);
  color: var(--text);
  box-shadow: 0 0 12px var(--primary-glow);
}

.exercise-item .ei-feedback {
  margin-top: 12px;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  display: none;
  line-height: 1.6;
}
.exercise-item .ei-feedback.correct {
  display: block;
  background: var(--success-glass);
  color: var(--success);
  border: 1px solid rgba(16,185,129,0.15);
}
.exercise-item .ei-feedback.wrong {
  display: block;
  background: var(--danger-glass);
  color: var(--danger);
  border: 1px solid rgba(239,68,68,0.15);
}

.exercise-item.done .ei-opt { pointer-events: none; opacity: 0.6; }

/* ============================================================
   刷题首页
   ============================================================ */
.practice-section { margin-bottom: 28px; }
.practice-section h3 {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 14px;
  color: var(--text);
  letter-spacing: -0.01em;
}

.practice-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
}

.practice-card {
  background: var(--bg-glass);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,0.05);
  border-radius: var(--radius);
  padding: 18px;
  cursor: pointer;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}
.practice-card::after {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background: linear-gradient(135deg, var(--primary-glass), transparent);
  opacity: 0;
  transition: opacity var(--transition);
}
.practice-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
  border-color: rgba(255,255,255,0.1);
}
.practice-card:hover::after { opacity: 1; }

.pc-title {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 6px;
  position: relative;
  z-index: 1;
}
.pc-desc {
  font-size: 12px;
  color: var(--text-dim);
  position: relative;
  z-index: 1;
}

/* ============================================================
   我的页面
   ============================================================ */
.plan-card {
  background: var(--bg-glass);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,0.05);
  border-radius: var(--radius);
  padding: 22px;
  margin-bottom: 16px;
}
.plan-card h3 { font-size: 16px; font-weight: 700; margin-bottom: 16px; }

.plan-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 0;
  font-size: 14px;
  border-bottom: 1px solid rgba(255,255,255,0.03);
}
.plan-row:last-of-type { border-bottom: none; }
.plan-label { color: var(--text-dim); }
.plan-value { color: var(--text); font-weight: 600; font-variant-numeric: tabular-nums; }

.plan-progress-bar {
  height: 8px;
  background: rgba(255,255,255,0.06);
  border-radius: 4px;
  margin-top: 14px;
  overflow: hidden;
}
.plan-progress-fill {
  height: 100%;
  border-radius: 4px;
  background: linear-gradient(90deg, var(--primary), var(--primary-light));
  box-shadow: 0 0 10px var(--primary-glow);
  transition: width 0.8s var(--ease-spring);
}

.plan-empty {
  text-align: center;
  padding: 24px 16px;
  color: var(--text-dim);
  font-size: 14px;
}
.plan-empty p { margin-bottom: 6px; }

.streak-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 12px;
  background: var(--gold-glass);
  border: 1px solid rgba(245,158,11,0.15);
  border-radius: var(--radius-full);
  font-size: 13px;
  color: var(--gold);
  font-weight: 600;
  margin-left: 8px;
  animation: streakPulse 2s ease-in-out infinite;
}
@keyframes streakPulse {
  0%, 100% { box-shadow: 0 0 0 0 var(--gold-glow); }
  50% { box-shadow: 0 0 12px 2px var(--gold-glow); }
}

.plan-actions { margin-top: 14px; }

.my-stat-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin-bottom: 16px;
}

.my-stat-item {
  background: var(--bg-glass);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,0.05);
  border-radius: var(--radius);
  padding: 18px 14px;
  text-align: center;
  transition: all var(--transition);
}
.my-stat-item:hover { border-color: rgba(255,255,255,0.1); transform: translateY(-1px); }

.my-stat-val {
  font-size: 26px;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--text), var(--primary-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.my-stat-item:nth-child(2) .my-stat-val {
  background: linear-gradient(135deg, var(--success), #34d399);
  -webkit-background-clip: text;
  background-clip: text;
}
.my-stat-item:nth-child(3) .my-stat-val {
  background: linear-gradient(135deg, var(--primary-light), #a78bfa);
  -webkit-background-clip: text;
  background-clip: text;
}
.my-stat-item:nth-child(4) .my-stat-val {
  background: linear-gradient(135deg, var(--gold), #fbbf24);
  -webkit-background-clip: text;
  background-clip: text;
}

.my-stat-lbl {
  font-size: 11px;
  color: var(--text-dim);
  margin-top: 6px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-weight: 500;
}

/* ============================================================
   测验/考试 题目卡片
   ============================================================ */
.quiz-card {
  background: var(--bg-glass);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,0.05);
  border-radius: var(--radius);
  padding: 24px 20px;
  margin-bottom: 16px;
}

.q-text {
  font-size: 16px;
  font-weight: 500;
  margin-bottom: 20px;
  line-height: 1.8;
  color: var(--text);
}

.q-option {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  margin-bottom: 8px;
  background: rgba(255,255,255,0.03);
  border: 1px solid rgba(255,255,255,0.06);
  border-radius: var(--radius);
  cursor: pointer;
  transition: all var(--transition-fast);
  user-select: none;
}
.q-option:hover { border-color: rgba(255,255,255,0.12); background: rgba(255,255,255,0.05); }
.q-option.selected {
  border-color: var(--primary);
  background: var(--primary-glass);
  box-shadow: 0 0 12px var(--primary-glow);
}

.q-opt-key {
  width: 32px; height: 32px;
  border-radius: 50%;
  background: rgba(255,255,255,0.06);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 700;
  flex-shrink: 0;
  transition: all var(--transition-fast);
}
.q-option.selected .q-opt-key {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 2px 8px var(--primary-glow);
}

.quiz-actions, .exam-actions {
  display: flex;
  gap: 10px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ============================================================
   考试导航
   ============================================================ */
.exam-topbar {
  border-bottom: 2px solid var(--primary);
}

.exam-timer {
  font-size: 18px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--gold);
  letter-spacing: 0.02em;
}

.exam-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
  padding: 12px 16px;
  background: rgba(18,18,26,0.5);
  backdrop-filter: blur(12px);
  max-height: 170px;
  overflow-y: auto;
  border-bottom: 1px solid rgba(255,255,255,0.04);
}
.en-item {
  width: 32px; height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 600;
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.06);
  border-radius: var(--radius-xs);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-variant-numeric: tabular-nums;
  user-select: none;
}
.en-item.answered {
  background: var(--success);
  color: #fff;
  border-color: var(--success);
  font-weight: 700;
}
.en-item.current {
  border: 2px solid var(--primary);
  box-shadow: 0 0 8px var(--primary-glow);
  font-weight: 700;
}
.en-item:hover { opacity: 0.85; transform: scale(1.05); }

/* ============================================================
   结果页
   ============================================================ */
.result-summary {
  text-align: center;
  padding: 28px 24px;
  background: var(--bg-glass);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,0.05);
  border-radius: var(--radius);
  margin-bottom: 16px;
}
.result-score {
  font-size: 72px;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1;
  margin-bottom: 8px;
  background: linear-gradient(135deg, var(--gold), #fbbf24);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.result-score.failed {
  background: linear-gradient(135deg, var(--danger), #f87171);
  -webkit-background-clip: text;
  background-clip: text;
}

.result-badge { font-size: 22px; margin: 10px 0; }
.result-detail { font-size: 14px; color: var(--text-dim); margin-top: 6px; }

.result-item {
  padding: 12px 16px;
  margin-bottom: 6px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  line-height: 1.6;
  border: 1px solid transparent;
}
.result-correct {
  background: var(--success-glass);
  border-color: rgba(16,185,129,0.1);
}
.result-wrong {
  background: var(--danger-glass);
  border-color: rgba(239,68,68,0.1);
}
.result-exp {
  font-size: 12px;
  color: var(--text-dim);
  margin-top: 6px;
  line-height: 1.6;
}

/* ============================================================
   错题本
   ============================================================ */
.filter-row { margin-bottom: 14px; }

.wrong-item {
  background: var(--bg-glass);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,0.04);
  border-left: 3px solid var(--danger);
  border-radius: var(--radius);
  padding: 16px;
  margin-bottom: 10px;
  transition: all var(--transition);
}
.wrong-item:hover { border-left-color: #f87171; }

.wi-header { display: flex; gap: 10px; align-items: center; margin-bottom: 10px; font-size: 12px; flex-wrap: wrap; }
.wi-subject { color: var(--primary-light); font-weight: 700; }
.wi-chapter { color: var(--text-dim); }
.wi-reviewed {
  color: var(--success);
  font-size: 11px;
  font-weight: 600;
  background: var(--success-glass);
  padding: 2px 8px;
  border-radius: var(--radius-xs);
}

.wi-question { font-size: 14px; margin-bottom: 10px; line-height: 1.6; }
.wi-answers { display: flex; gap: 18px; font-size: 13px; margin-bottom: 10px; }
.wi-wrong { color: var(--danger); }
.wi-correct { color: var(--success); }
.wi-exp { font-size: 12px; color: var(--text-dim); margin-bottom: 10px; line-height: 1.6; }
.wi-actions { display: flex; gap: 8px; }

/* ============================================================
   管理后台
   ============================================================ */
.admin-tabs { display: flex; gap: 8px; margin-bottom: 18px; flex-wrap: wrap; }

.admin-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  font-size: 12px;
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 1px solid rgba(255,255,255,0.05);
}
.admin-table th, .admin-table td {
  padding: 8px 10px;
  text-align: left;
  border-bottom: 1px solid rgba(255,255,255,0.03);
}
.admin-table th {
  color: var(--text-dim);
  font-weight: 600;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  background: var(--bg-glass);
}
.admin-table tr:hover td { background: rgba(255,255,255,0.015); }

.pagination {
  display: flex;
  gap: 6px;
  margin-top: 18px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ============================================================
   考试历史
   ============================================================ */
.exam-history-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 16px;
  background: var(--bg-glass);
  border: 1px solid rgba(255,255,255,0.04);
  border-radius: var(--radius);
  margin-bottom: 6px;
  cursor: pointer;
  font-size: 13px;
  transition: all var(--transition-fast);
  border-left: 3px solid transparent;
}
.exam-history-item.passed { border-left-color: var(--success); }
.exam-history-item.failed { border-left-color: var(--danger); }
.exam-history-item:hover { border-color: rgba(255,255,255,0.1); transform: translateX(2px); }

/* ============================================================
   模态框
   ============================================================ */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  backdrop-filter: blur(4px);
  z-index: 100;
  display: flex;
  align-items: flex-end;
  justify-content: center;
}

.modal-sheet {
  background: var(--bg-surface);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--radius-xl) var(--radius-xl) 0 0;
  width: 100%;
  max-width: 520px;
  max-height: 85vh;
  overflow-y: auto;
  padding: 24px 20px 32px;
  box-shadow: 0 -8px 40px rgba(0,0,0,0.5);
  animation: slideUp 0.35s var(--ease-spring);
}
@media (min-width: 768px) {
  .modal-sheet {
    border-radius: var(--radius-xl);
    margin: 40px 20px;
    max-height: 80vh;
  }
}

.modal-handle {
  width: 36px;
  height: 4px;
  background: rgba(255,255,255,0.15);
  border-radius: 2px;
  margin: 0 auto 20px;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}
.modal-header h3 { font-size: 18px; font-weight: 700; }
.modal-body { padding-bottom: 16px; }

@keyframes slideUp {
  from { transform: translateY(100%); }
  to { transform: translateY(0); }
}

/* ============================================================
   Toast 通知
   ============================================================ */
#toast-container {
  position: fixed;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 200;
  display: flex;
  flex-direction: column;
  gap: 8px;
  pointer-events: none;
}

.toast {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  border-radius: var(--radius-full);
  font-size: 14px;
  font-weight: 600;
  color: #fff;
  pointer-events: auto;
  backdrop-filter: blur(12px);
  border: 1px solid rgba(255,255,255,0.08);
  box-shadow: var(--shadow-lg);
  animation: toastIn 0.35s var(--ease-spring);
  transition: opacity 0.3s var(--ease);
}
.toast-success { background: rgba(16,185,129,0.85); }
.toast-error { background: rgba(239,68,68,0.85); }
.toast-info { background: rgba(99,102,241,0.85); }
.toast.fadeout { opacity: 0; }

@keyframes toastIn {
  from { opacity: 0; transform: translateY(-12px) scale(0.95); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

/* ============================================================
   全局动画
   ============================================================ */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(14px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* ============================================================
   响应式
   ============================================================ */
@media (min-width: 600px) {
  .stats-grid { grid-template-columns: repeat(4, 1fr); gap: 12px; }
  .practice-grid { grid-template-columns: repeat(2, 1fr); }
  .my-stat-grid { grid-template-columns: repeat(4, 1fr); }
}

@media (min-width: 768px) {
  .content {
    padding: 28px 32px;
    padding-bottom: 120px;
  }

  .section-content { padding: 32px 28px; }

  .quiz-card { padding: 32px 28px; }
  .q-text { font-size: 18px; }

  .exam-nav { max-height: 200px; padding: 12px 24px; }
  .en-item { width: 36px; height: 36px; font-size: 13px; }

  .login-container { margin-top: 120px; padding: 48px 40px; }

  .bottom-nav { max-width: 480px; }
}

@media (min-width: 1024px) {
  .content { padding: 36px 48px; padding-bottom: 120px; }
  .section-content { padding: 40px 36px; }
  .section-content h3 { font-size: 22px; }
  .section-content { font-size: 16px; }
}

/* 移动端底部安全区 */
@supports (padding-bottom: env(safe-area-inset-bottom)) {
  .bottom-nav {
    padding-bottom: calc(6px + env(safe-area-inset-bottom));
  }
  .content {
    padding-bottom: calc(120px + env(safe-area-inset-bottom));
  }
}