/* ============================================
   暑假学习计划 - 共享样式表
   设计方向：温暖、学术、清爽的"学者笔记本"风格
   ============================================ */

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

/* --- CSS 变量 --- */
:root {
  /* 主色调 */
  --bg-page: #f5f1e8;
  --bg-card: #ffffff;
  --bg-soft: #faf7f0;
  --bg-section: #fdfbf5;

  /* 文字色 */
  --text-primary: #1a2b3c;
  --text-secondary: #5a6c7e;
  --text-tertiary: #8a9bae;
  --text-inverse: #ffffff;

  /* 主题色 */
  --color-primary: #1a5670;
  --color-primary-light: #2d7a96;
  --color-primary-dark: #0f3d52;
  --color-primary-bg: #e8f0f4;

  /* 强调色 */
  --color-accent: #d97c2e;
  --color-accent-light: #f0a050;
  --color-accent-bg: #fdf0e0;

  /* 功能色 */
  --color-goal: #2d7a4a;
  --color-goal-bg: #e6f4ea;
  --color-content: #1a5670;
  --color-content-bg: #e8f0f4;
  --color-assess: #b8453e;
  --color-assess-bg: #fcebe9;
  --color-success: #2d8659;
  --color-warning: #d97c2e;

  /* 边框 */
  --border-color: #e0d8c8;
  --border-light: #ede8db;
  --border-card: #d8d0c0;

  /* 阴影 */
  --shadow-sm: 0 1px 3px rgba(26, 43, 60, 0.06);
  --shadow-md: 0 4px 12px rgba(26, 43, 60, 0.08);
  --shadow-lg: 0 8px 28px rgba(26, 43, 60, 0.12);

  /* 间距 */
  --space-xs: 0.375rem;
  --space-sm: 0.625rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2.5rem;
  --space-2xl: 3.5rem;

  /* 圆角 */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;

  /* 字体 */
  --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
  --font-mono: "JetBrains Mono", "Fira Code", "Consolas", monospace;
  --font-serif: "Noto Serif SC", "Songti SC", "SimSun", serif;

  /* 过渡 */
  --transition: all 0.25s ease;
  --transition-slow: all 0.4s ease;
}

/* --- 基础排版 --- */
html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  background-color: var(--bg-page);
  color: var(--text-primary);
  line-height: 1.75;
  font-size: 15px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background-image:
    radial-gradient(circle at 20% 50%, rgba(217, 124, 46, 0.03) 0%, transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(26, 86, 112, 0.03) 0%, transparent 50%);
  background-attachment: fixed;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: var(--transition);
}

a:hover {
  color: var(--color-accent);
}

/* --- 导航栏 --- */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.navbar-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.625rem var(--space-lg);
  flex-wrap: wrap;
  gap: 0.5rem;
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-primary);
  white-space: nowrap;
}

.navbar-brand .brand-icon {
  font-size: 1.3rem;
}

.navbar-links {
  display: flex;
  gap: 0.25rem;
  list-style: none;
  flex-wrap: wrap;
}

.navbar-links a {
  display: block;
  padding: 0.4rem 0.85rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: var(--transition);
}

.navbar-links a:hover,
.navbar-links a.active {
  background: var(--color-primary-bg);
  color: var(--color-primary);
}

.navbar-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--color-primary);
}

/* --- 容器 --- */
.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: var(--space-xl) var(--space-lg);
}

.container-narrow {
  max-width: 820px;
  margin: 0 auto;
  padding: var(--space-xl) var(--space-lg);
}

/* --- 页面标题区 --- */
.page-header {
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 50%, var(--color-primary-light) 100%);
  color: var(--text-inverse);
  padding: var(--space-2xl) var(--space-lg) var(--space-xl);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.page-header::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-image:
    radial-gradient(circle at 15% 30%, rgba(255, 255, 255, 0.08) 0%, transparent 40%),
    radial-gradient(circle at 85% 70%, rgba(217, 124, 46, 0.1) 0%, transparent 40%);
}

.page-header h1 {
  position: relative;
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: 0.02em;
  margin-bottom: 0.5rem;
}

.page-header .subtitle {
  position: relative;
  font-size: 1rem;
  opacity: 0.85;
  max-width: 600px;
  margin: 0 auto;
}

.page-header .header-meta {
  position: relative;
  display: flex;
  justify-content: center;
  gap: var(--space-lg);
  margin-top: var(--space-md);
  font-size: 0.85rem;
  opacity: 0.75;
  flex-wrap: wrap;
}

/* --- 卡片 --- */
.card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-card);
  overflow: hidden;
  transition: var(--transition);
}

.card:hover {
  box-shadow: var(--shadow-lg);
}

.card-body {
  padding: var(--space-lg);
}

/* --- 通用按钮 --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.55rem 1.25rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  font-family: var(--font-body);
}

.btn-primary {
  background: var(--color-primary);
  color: var(--text-inverse);
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  color: var(--text-inverse);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-accent {
  background: var(--color-accent);
  color: var(--text-inverse);
}

.btn-accent:hover {
  background: #c06d20;
  color: var(--text-inverse);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--color-primary);
  color: var(--color-primary);
}

.btn-outline:hover {
  background: var(--color-primary);
  color: var(--text-inverse);
}

/* --- 标签/徽章 --- */
.badge {
  display: inline-block;
  padding: 0.2rem 0.6rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.badge-goal {
  background: var(--color-goal-bg);
  color: var(--color-goal);
}

.badge-content {
  background: var(--color-content-bg);
  color: var(--color-content);
}

.badge-assess {
  background: var(--color-assess-bg);
  color: var(--color-assess);
}

.badge-source {
  background: #f0eee8;
  color: var(--text-secondary);
  font-weight: 400;
  font-size: 0.7rem;
}

/* --- 周次导航 --- */
.week-nav {
  display: flex;
  gap: 0.5rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: var(--space-xl);
}

.week-nav a {
  padding: 0.6rem 1.5rem;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.9rem;
  background: var(--bg-card);
  color: var(--text-secondary);
  border: 2px solid var(--border-color);
  transition: var(--transition);
}

.week-nav a:hover,
.week-nav a.active {
  background: var(--color-primary);
  color: var(--text-inverse);
  border-color: var(--color-primary);
}

/* --- 日计划布局 --- */
.day-section {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-card);
  margin-bottom: var(--space-xl);
  overflow: hidden;
}

.day-header {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
  color: var(--text-inverse);
  padding: var(--space-md) var(--space-lg);
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  user-select: none;
  transition: var(--transition);
}

.day-header:hover {
  filter: brightness(1.05);
}

.day-header-left {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.day-number {
  background: rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-sm);
  padding: 0.25rem 0.75rem;
  font-size: 0.85rem;
  font-weight: 700;
}

.day-title {
  font-size: 1.1rem;
  font-weight: 700;
}

.day-date {
  font-size: 0.8rem;
  opacity: 0.8;
}

.day-toggle {
  font-size: 1.2rem;
  transition: transform 0.3s ease;
}

.day-section.collapsed .day-toggle {
  transform: rotate(-90deg);
}

.day-content, .day-body {
  padding: var(--space-lg);
}

.day-section.collapsed .day-content,
.day-section.collapsed .day-body {
  display: none;
}

/* --- 学习目标区 --- */
.section-block {
  margin-bottom: var(--space-lg);
}

.section-block:last-child {
  margin-bottom: 0;
}

.section-title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: var(--space-sm);
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--border-light);
}

.section-title .icon {
  font-size: 1.15rem;
}

.section-title.goal {
  color: var(--color-goal);
  border-color: var(--color-goal-bg);
}

.section-title.content {
  color: var(--color-content);
  border-color: var(--color-content-bg);
}

.section-title.assess {
  color: var(--color-assess);
  border-color: var(--color-assess-bg);
}

/* --- 目标列表 --- */
.goal-list {
  list-style: none;
  padding: 0;
}

.goal-list li {
  position: relative;
  padding-left: 1.75rem;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.goal-list li::before {
  content: "▶";
  position: absolute;
  left: 0;
  color: var(--color-goal);
  font-size: 0.75rem;
  top: 0.15rem;
}

/* --- 学习内容区 --- */
.content-block {
  background: var(--bg-soft);
  border-radius: var(--radius-md);
  padding: var(--space-md) var(--space-lg);
  margin-bottom: var(--space-md);
  border-left: 4px solid var(--color-primary-light);
}

.content-block h4 {
  color: var(--color-primary);
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.content-block p {
  color: var(--text-primary);
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
}

.content-block ul,
.content-block ol {
  padding-left: 1.25rem;
  margin-bottom: 0.5rem;
}

.content-block li {
  font-size: 0.875rem;
  margin-bottom: 0.3rem;
}

.content-block .formula {
  display: inline-block;
  background: var(--bg-card);
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--color-primary);
  border: 1px solid var(--border-light);
}

.source-ref {
  display: inline-block;
  font-size: 0.7rem;
  color: var(--text-tertiary);
  background: #f0eee8;
  padding: 0.1rem 0.4rem;
  border-radius: 3px;
  margin-left: 0.3rem;
  vertical-align: super;
  font-weight: 400;
}

/* --- 考核题目区 --- */
.question-list {
  counter-reset: q-counter;
}

.question-item {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  margin-bottom: var(--space-sm);
  transition: var(--transition);
}

.question-item:hover {
  border-color: var(--color-accent-light);
  box-shadow: var(--shadow-sm);
}

.question-item header {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.question-number {
  counter-increment: q-counter;
  background: var(--color-assess);
  color: var(--text-inverse);
  border-radius: 50%;
  width: 1.5rem;
  height: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
  flex-shrink: 0;
}

.question-number::before {
  content: counter(q-counter);
}

.question-text {
  font-size: 0.9rem;
  color: var(--text-primary);
  flex: 1;
  line-height: 1.7;
}

.question-text .formula {
  display: inline-block;
  background: var(--bg-soft);
  padding: 0.1rem 0.4rem;
  border-radius: 3px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

/* --- 折叠答案 --- */
.answer-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  background: var(--color-assess-bg);
  color: var(--color-assess);
  border: 1px solid var(--color-assess);
  border-radius: var(--radius-sm);
  padding: 0.3rem 0.85rem;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font-body);
  margin-top: 0.5rem;
}

.answer-toggle:hover {
  background: var(--color-assess);
  color: var(--text-inverse);
}

.answer-toggle .arrow {
  transition: transform 0.3s ease;
  display: inline-block;
}

.answer-toggle.open .arrow {
  transform: rotate(180deg);
}

.answer-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.4s ease;
  padding: 0 var(--space-md);
  background: var(--color-assess-bg);
  border-radius: var(--radius-sm);
  margin-top: 0;
}

.answer-content.open {
  max-height: 1200px;
  padding: var(--space-md);
  margin-top: 0.5rem;
}

.answer-content h5 {
  color: var(--color-assess);
  font-size: 0.85rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
}

.answer-content p,
.answer-content li {
  font-size: 0.85rem;
  color: var(--text-primary);
  line-height: 1.8;
}

.answer-content .answer-final {
  display: inline-block;
  background: var(--color-success);
  color: var(--text-inverse);
  padding: 0.15rem 0.6rem;
  border-radius: 4px;
  font-weight: 700;
  font-size: 0.85rem;
  font-family: var(--font-mono);
}

.answer-content ol {
  padding-left: 1.25rem;
  margin: 0.4rem 0;
}

.answer-content .step {
  margin-bottom: 0.4rem;
}

/* --- 评分反馈区 --- */
.feedback-box {
  background: var(--bg-soft);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  margin-top: var(--space-lg);
  border: 1px dashed var(--border-card);
}

.feedback-box h4 {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}

.feedback-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.score-input {
  width: 50px;
  padding: 0.3rem;
  text-align: center;
  border: 1px solid var(--border-card);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
}

.feedback-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* --- 乘法口诀表 --- */
.mult-container {
  max-width: 100%;
  overflow-x: auto;
  padding: var(--space-md) 0;
}

.mult-table {
  border-collapse: collapse;
  margin: 0 auto;
  font-family: var(--font-body);
  font-size: 0.85rem;
}

.mult-table th,
.mult-table td {
  border: 1px solid var(--border-light);
  text-align: center;
  padding: 0.35rem 0.5rem;
  min-width: 42px;
  height: 32px;
}

.mult-table thead th {
  background: var(--color-primary);
  color: var(--text-inverse);
  font-weight: 700;
  position: sticky;
  top: 0;
  z-index: 10;
}

.mult-table tbody th {
  background: var(--color-primary-light);
  color: var(--text-inverse);
  font-weight: 700;
}

.mult-table td {
  background: var(--bg-card);
  transition: var(--transition);
  cursor: default;
}

.mult-table td:hover {
  background: var(--color-accent-bg);
}

.mult-table .easy {
  background: #e6f4ea;
}

.mult-table .medium {
  background: #fff8e7;
}

.mult-table .hard {
  background: #fcebe9;
}

.mult-table .diagonal {
  background: var(--color-primary-bg);
  font-weight: 700;
  color: var(--color-primary);
}

/* 自测模式 */
.mult-table.test-mode td:not(.diagonal):not(:empty) {
  color: transparent;
  cursor: pointer;
}

.mult-table.test-mode td.revealed {
  color: var(--text-primary);
  background: var(--color-success);
  color: var(--text-inverse);
}

.mult-table.test-mode td.wrong {
  background: var(--color-assess);
  color: var(--text-inverse);
}

.mode-toggle-bar {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
  flex-wrap: wrap;
}

.mode-btn {
  padding: 0.5rem 1.25rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 600;
  border: 2px solid var(--border-color);
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font-body);
}

.mode-btn.active {
  background: var(--color-primary);
  color: var(--text-inverse);
  border-color: var(--color-primary);
}

/* 乘法口诀分段列表 */
.mult-sections {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--space-md);
  margin-top: var(--space-lg);
}

.mult-section-card {
  background: var(--bg-card);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-card);
  padding: var(--space-md);
  box-shadow: var(--shadow-sm);
}

.mult-section-card h4 {
  color: var(--color-primary);
  font-size: 0.95rem;
  margin-bottom: 0.5rem;
  padding-bottom: 0.4rem;
  border-bottom: 2px solid var(--color-primary-bg);
}

.mult-section-card .formula-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
  margin-bottom: 0.3rem;
}

.mult-section-card .formula-item {
  background: var(--bg-soft);
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-primary);
  transition: var(--transition);
}

.mult-section-card .formula-item:hover {
  background: var(--color-accent-bg);
}

/* 技巧提示框 */
.tip-box {
  background: var(--color-accent-bg);
  border-left: 4px solid var(--color-accent);
  border-radius: var(--radius-sm);
  padding: var(--space-md) var(--space-lg);
  margin: var(--space-lg) 0;
}

.tip-box h4 {
  color: var(--color-accent);
  font-size: 0.95rem;
  margin-bottom: 0.5rem;
}

.tip-box p,
.tip-box li {
  font-size: 0.875rem;
  color: var(--text-primary);
}

.tip-box table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 0.5rem;
  font-size: 0.8rem;
}

.tip-box th,
.tip-box td {
  border: 1px solid var(--border-color);
  padding: 0.3rem 0.5rem;
  text-align: center;
}

.tip-box th {
  background: var(--color-accent);
  color: var(--text-inverse);
}

/* --- 几何模型 --- */
.model-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-card);
  margin-bottom: var(--space-xl);
  overflow: hidden;
}

.model-header {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
  color: var(--text-inverse);
  padding: var(--space-md) var(--space-lg);
}

.model-header h3 {
  font-size: 1.15rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.model-header .model-aliases {
  font-size: 0.8rem;
  opacity: 0.8;
  margin-top: 0.2rem;
}

.model-body {
  padding: var(--space-lg);
}

.model-diagram {
  background: var(--bg-soft);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  display: flex;
  justify-content: center;
  align-items: center;
  margin-bottom: var(--space-md);
  border: 1px solid var(--border-light);
  min-height: 200px;
}

.model-diagram svg {
  max-width: 100%;
  height: auto;
}

.model-section {
  margin-bottom: var(--space-md);
}

.model-section h4 {
  color: var(--color-primary);
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.3rem;
}

.model-section p {
  font-size: 0.875rem;
  color: var(--text-primary);
  line-height: 1.8;
  margin-bottom: 0.4rem;
}

.model-section .key-point {
  background: var(--color-accent-bg);
  border-radius: var(--radius-sm);
  padding: 0.5rem 0.75rem;
  font-size: 0.875rem;
  margin: 0.5rem 0;
  border-left: 3px solid var(--color-accent);
}

.model-section .key-point strong {
  color: var(--color-accent);
}

/* --- 网格布局 --- */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-md);
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-md);
}

/* --- 概览卡片 --- */
.overview-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-card);
  transition: var(--transition);
}

.overview-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
}

.overview-card .card-icon {
  font-size: 2rem;
  margin-bottom: 0.5rem;
}

.overview-card h3 {
  font-size: 1.05rem;
  color: var(--color-primary);
  margin-bottom: 0.5rem;
}

.overview-card p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* --- 时间线 --- */
.timeline {
  position: relative;
  padding-left: 2rem;
  margin: var(--space-lg) 0;
}

.timeline::before {
  content: "";
  position: absolute;
  left: 0.5rem;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--color-primary-light);
  opacity: 0.3;
}

.timeline-item {
  position: relative;
  margin-bottom: var(--space-lg);
}

.timeline-item::before {
  content: "";
  position: absolute;
  left: -1.6rem;
  top: 0.3rem;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--color-primary);
  border: 3px solid var(--bg-page);
}

.timeline-item h4 {
  font-size: 0.95rem;
  color: var(--color-primary);
  margin-bottom: 0.3rem;
}

.timeline-item p {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* --- 提示框 --- */
.callout {
  background: var(--color-primary-bg);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-sm);
  padding: var(--space-md) var(--space-lg);
  margin: var(--space-md) 0;
}

.callout p {
  font-size: 0.875rem;
  color: var(--text-primary);
}

.callout strong {
  color: var(--color-primary);
}

/* --- 表格 --- */
.data-table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--space-md) 0;
  font-size: 0.85rem;
}

.data-table th,
.data-table td {
  border: 1px solid var(--border-color);
  padding: 0.5rem 0.75rem;
  text-align: left;
}

.data-table th {
  background: var(--color-primary);
  color: var(--text-inverse);
  font-weight: 700;
}

.data-table tbody tr:nth-child(even) {
  background: var(--bg-soft);
}

.data-table tbody tr:hover {
  background: var(--color-primary-bg);
}

/* --- 进度条 --- */
.progress-bar-container {
  background: var(--border-light);
  border-radius: 20px;
  height: 8px;
  overflow: hidden;
  margin: 0.5rem 0;
}

.progress-bar-fill {
  background: linear-gradient(90deg, var(--color-primary), var(--color-primary-light));
  height: 100%;
  border-radius: 20px;
  transition: width 0.5s ease;
}

/* --- 页脚 --- */
.footer {
  background: var(--color-primary-dark);
  color: var(--text-inverse);
  padding: var(--space-xl) var(--space-lg);
  text-align: center;
  margin-top: var(--space-2xl);
}

.footer p {
  font-size: 0.8rem;
  opacity: 0.7;
  margin-bottom: 0.3rem;
}

.footer .footer-sources {
  max-width: 800px;
  margin: var(--space-md) auto 0;
  font-size: 0.75rem;
  opacity: 0.5;
  line-height: 1.6;
}

/* --- 页面导航 --- */
.page-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: var(--space-xl);
  padding-top: var(--space-lg);
  border-top: 2px solid var(--border-light);
}

.page-nav a {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.875rem;
  font-weight: 600;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

.page-nav a:hover {
  background: var(--color-primary-bg);
}

/* --- 响应式 --- */
@media (max-width: 768px) {
  html { font-size: 15px; }

  .navbar-links {
    display: none;
    width: 100%;
    flex-direction: column;
    padding-top: 0.5rem;
  }

  .navbar-links.show {
    display: flex;
  }

  .navbar-toggle {
    display: block;
  }

  .container {
    padding: var(--space-lg) var(--space-md);
  }

  .page-header h1 {
    font-size: 1.5rem;
  }

  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .day-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.3rem;
  }

  .mult-table th,
  .mult-table td {
    min-width: 32px;
    padding: 0.2rem 0.3rem;
    font-size: 0.75rem;
  }

  .mult-sections {
    grid-template-columns: 1fr;
  }
}

/* --- 动画 --- */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeInUp 0.5s ease forwards;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.6; }
}

.pulse {
  animation: pulse 2s infinite;
}

/* --- 工具类 --- */
.text-center { text-align: center; }
.text-right { text-align: right; }
.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.hidden { display: none; }
.text-primary { color: var(--color-primary); }
.text-accent { color: var(--color-accent); }
.text-secondary { color: var(--text-secondary); }
.text-success { color: var(--color-success); }
.font-bold { font-weight: 700; }
.font-mono { font-family: var(--font-mono); }

/* ============================================
   新增：选择题/判断题样式
   ============================================ */

/* --- 学科标签 --- */
.subject-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.2rem 0.7rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}
.subject-badge.math { background: #e8f0f4; color: #1a5670; }
.subject-badge.chinese { background: #fcebe9; color: #b8453e; }
.subject-badge.english { background: #e6f4ea; color: #2d7a4a; }

/* --- 学科分区 --- */
.subject-section {
  margin-bottom: var(--space-xl);
}
.subject-section-header {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.05rem;
  font-weight: 700;
  padding: 0.6rem var(--space-md);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-md);
}
.subject-section-header.math {
  background: linear-gradient(135deg, #1a5670 0%, #2d7a96 100%);
  color: #fff;
}
.subject-section-header.chinese {
  background: linear-gradient(135deg, #b8453e 0%, #d4665e 100%);
  color: #fff;
}
.subject-section-header.english {
  background: linear-gradient(135deg, #2d7a4a 0%, #4a9d6a 100%);
  color: #fff;
}

/* --- Quiz 题目容器 --- */
.quiz-question {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  margin-bottom: var(--space-sm);
  transition: var(--transition);
  position: relative;
}
.quiz-question:hover {
  border-color: var(--color-accent-light);
  box-shadow: var(--shadow-sm);
}
.quiz-question.correct {
  border-color: var(--color-success);
  background: #f0faf4;
}
.quiz-question.wrong {
  border-color: var(--color-assess);
  background: #fef5f5;
}

/* --- Quiz 题目头部 --- */
.quiz-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}
.quiz-number {
  background: var(--color-assess);
  color: #fff;
  border-radius: 50%;
  width: 1.5rem;
  height: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
  flex-shrink: 0;
}
.quiz-time {
  font-size: 0.72rem;
  color: var(--text-tertiary);
  background: #f0eee8;
  padding: 0.1rem 0.5rem;
  border-radius: 10px;
  display: inline-flex;
  align-items: center;
  gap: 0.2rem;
}
.quiz-type-badge {
  font-size: 0.68rem;
  padding: 0.1rem 0.4rem;
  border-radius: 3px;
  font-weight: 600;
}
.quiz-type-badge.choice { background: var(--color-primary-bg); color: var(--color-primary); }
.quiz-type-badge.judge { background: var(--color-accent-bg); color: var(--color-accent); }

/* --- Quiz 题目文本 --- */
.quiz-text {
  font-size: 0.9rem;
  color: var(--text-primary);
  line-height: 1.7;
  margin-bottom: 0.6rem;
  padding-left: 2rem;
}
.quiz-text .formula {
  display: inline-block;
  background: var(--bg-soft);
  padding: 0.1rem 0.4rem;
  border-radius: 3px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

/* --- Quiz 选项 --- */
.quiz-options {
  padding-left: 2rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  margin-bottom: 0.6rem;
}
.quiz-option {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition);
  font-size: 0.875rem;
  line-height: 1.6;
}
.quiz-option:hover {
  background: var(--color-primary-bg);
  border-color: var(--color-primary-light);
}
.quiz-option input[type="radio"] {
  margin-top: 0.2rem;
  accent-color: var(--color-primary);
  flex-shrink: 0;
}
.quiz-option .option-label {
  font-weight: 700;
  color: var(--color-primary);
  flex-shrink: 0;
  min-width: 1.2rem;
}
.quiz-option .option-text {
  color: var(--text-primary);
}
.quiz-option.selected {
  background: var(--color-primary-bg);
  border-color: var(--color-primary);
}
/* 答题后状态 */
.quiz-question.correct .quiz-option:has(input[value=""]:not([value])) { }
.quiz-option.correct-option {
  background: #e6f4ea !important;
  border-color: var(--color-success) !important;
  color: var(--color-success);
}
.quiz-option.correct-option .option-label {
  color: var(--color-success);
}
.quiz-option.wrong-option {
  background: #fcebe9 !important;
  border-color: var(--color-assess) !important;
}
.quiz-option.wrong-option .option-label {
  color: var(--color-assess);
}

/* --- 提交按钮 --- */
.quiz-submit {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--color-primary);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  padding: 0.4rem 1.1rem;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font-body);
  margin-left: 2rem;
}
.quiz-submit:hover {
  background: var(--color-primary-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}
.quiz-submit:disabled {
  background: var(--text-tertiary);
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

/* --- 反馈区 --- */
.quiz-feedback {
  margin-left: 2rem;
  margin-top: 0.5rem;
  font-size: 0.85rem;
  font-weight: 600;
  display: none;
}
.quiz-feedback.show { display: block; }
.quiz-feedback.correct {
  color: var(--color-success);
}
.quiz-feedback.wrong {
  color: var(--color-assess);
}

/* --- 解析区 --- */
.quiz-explanation {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.4s ease, margin 0.4s ease;
  padding: 0 var(--space-md);
  background: var(--bg-soft);
  border-radius: var(--radius-sm);
  margin-left: 2rem;
}
.quiz-explanation.show {
  max-height: 800px;
  padding: var(--space-md);
  margin-top: 0.5rem;
}
.quiz-explanation h5 {
  color: var(--color-primary);
  font-size: 0.85rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
}
.quiz-explanation p,
.quiz-explanation li {
  font-size: 0.83rem;
  color: var(--text-primary);
  line-height: 1.8;
}
.quiz-explanation .answer-final {
  display: inline-block;
  background: var(--color-success);
  color: #fff;
  padding: 0.15rem 0.6rem;
  border-radius: 4px;
  font-weight: 700;
  font-size: 0.85rem;
  font-family: var(--font-mono);
}

/* --- 考核统计条 --- */
.quiz-stats-bar {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  background: var(--bg-soft);
  border-radius: var(--radius-md);
  padding: 0.6rem var(--space-md);
  margin-bottom: var(--space-md);
  border: 1px solid var(--border-light);
  flex-wrap: wrap;
  font-size: 0.82rem;
}
.quiz-stat-item {
  display: flex;
  align-items: center;
  gap: 0.3rem;
}
.quiz-stat-item .stat-num {
  font-weight: 700;
  font-size: 1rem;
}
.quiz-stat-item .stat-correct { color: var(--color-success); }
.quiz-stat-item .stat-wrong { color: var(--color-assess); }
.quiz-stat-item .stat-total { color: var(--color-primary); }
.quiz-stat-item .stat-time { color: var(--color-accent); }

/* ============================================
   新增：错题本样式
   ============================================ */
.error-card {
  background: var(--bg-card);
  border: 1px solid var(--color-assess);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  margin-bottom: var(--space-md);
  border-left: 4px solid var(--color-assess);
}
.error-card .error-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.5rem;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.error-card .error-question {
  font-size: 0.88rem;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  line-height: 1.7;
}
.error-card .error-answers {
  display: flex;
  gap: var(--space-md);
  font-size: 0.82rem;
  margin-bottom: 0.5rem;
  flex-wrap: wrap;
}
.error-card .error-user {
  color: var(--color-assess);
}
.error-card .error-correct {
  color: var(--color-success);
}
.error-card .error-explanation {
  font-size: 0.82rem;
  color: var(--text-secondary);
  background: var(--bg-soft);
  padding: 0.5rem;
  border-radius: var(--radius-sm);
}
.error-card .error-actions {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.5rem;
}
.error-card .btn-remove {
  background: var(--color-assess-bg);
  color: var(--color-assess);
  border: 1px solid var(--color-assess);
  border-radius: var(--radius-sm);
  padding: 0.25rem 0.7rem;
  font-size: 0.78rem;
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font-body);
}
.error-card .btn-remove:hover {
  background: var(--color-assess);
  color: #fff;
}
.error-empty {
  text-align: center;
  padding: var(--space-2xl) var(--space-lg);
  color: var(--text-tertiary);
}
.error-empty .empty-icon {
  font-size: 3rem;
  margin-bottom: var(--space-md);
}

/* --- 错题本筛选 --- */
.error-filter-bar {
  display: flex;
  gap: 0.5rem;
  margin-bottom: var(--space-lg);
  flex-wrap: wrap;
}
.error-filter-btn {
  padding: 0.35rem 0.9rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  border: 2px solid var(--border-color);
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font-body);
}
.error-filter-btn.active {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

/* ============================================
   新增：进度统计面板
   ============================================ */
.progress-panel {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-card);
  padding: var(--space-lg);
  margin-bottom: var(--space-xl);
}
.progress-panel h3 {
  font-size: 1.05rem;
  color: var(--color-primary);
  margin-bottom: var(--space-md);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.progress-stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: var(--space-md);
  margin-bottom: var(--space-md);
}
.progress-stat-box {
  background: var(--bg-soft);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  text-align: center;
  border: 1px solid var(--border-light);
}
.progress-stat-box .stat-value {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--color-primary);
  line-height: 1.2;
}
.progress-stat-box .stat-label {
  font-size: 0.78rem;
  color: var(--text-secondary);
  margin-top: 0.2rem;
}
.progress-stat-box.green .stat-value { color: var(--color-success); }
.progress-stat-box.red .stat-value { color: var(--color-assess); }
.progress-stat-box.orange .stat-value { color: var(--color-accent); }
.progress-subject-row {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: 0.5rem;
  flex-wrap: wrap;
}
.progress-subject-label {
  font-size: 0.85rem;
  font-weight: 600;
  min-width: 60px;
}
.progress-subject-label.math { color: var(--color-primary); }
.progress-subject-label.chinese { color: var(--color-assess); }
.progress-subject-label.english { color: var(--color-goal); }
.progress-subject-bar {
  flex: 1;
  min-width: 120px;
  height: 10px;
  background: var(--border-light);
  border-radius: 10px;
  overflow: hidden;
}
.progress-subject-fill {
  height: 100%;
  border-radius: 10px;
  transition: width 0.5s ease;
}
.progress-subject-fill.math { background: var(--color-primary); }
.progress-subject-fill.chinese { background: var(--color-assess); }
.progress-subject-fill.english { background: var(--color-goal); }
.progress-subject-text {
  font-size: 0.78rem;
  color: var(--text-secondary);
  min-width: 60px;
  text-align: right;
}