/* ============================================
   培训规划指南 - 样式表
   风格: 教程风格 (tutorial)
   主色调: #20c997
   ============================================ */

/* CSS 变量定义 */
:root {
  --accent-color: #20c997;
  --accent-dark: #1ba87e;
  --accent-light: #e6f9f3;
  --text-primary: #2c3e50;
  --text-secondary: #5a6c7d;
  --text-muted: #8b9aa8;
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #f1f3f5;
  --border-color: #e9ecef;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --max-width: 1200px;
  --header-height: 64px;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
}

a {
  color: var(--accent-color);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

ul, ol {
  list-style: none;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* ============================================
   通用组件
   ============================================ */

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1.5rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--accent-color);
  display: inline-block;
}

.card {
  background: var(--bg-primary);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
  transition: box-shadow 0.2s ease, transform 0.2s ease;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.625rem 1.25rem;
  font-size: 0.9375rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-primary {
  background: var(--accent-color);
  color: white;
}

.btn-primary:hover {
  background: var(--accent-dark);
  color: white;
}

.btn-outline {
  background: transparent;
  color: var(--accent-color);
  border: 1px solid var(--accent-color);
}

.btn-outline:hover {
  background: var(--accent-light);
}

/* 进度条组件 */
.progress-bar {
  width: 100%;
  height: 8px;
  background: var(--bg-tertiary);
  border-radius: 4px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-color), var(--accent-dark));
  border-radius: 4px;
  transition: width 0.3s ease;
}

.progress-text {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-top: 0.5rem;
}

/* 标签 */
.tag {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 500;
  border-radius: 20px;
  background: var(--accent-light);
  color: var(--accent-dark);
}

/* 面包屑 */
.breadcrumb {
  padding: 1rem 0;
  font-size: 0.875rem;
  color: var(--text-muted);
}

.breadcrumb a {
  color: var(--text-secondary);
}

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

.breadcrumb span {
  margin: 0 0.5rem;
}

/* ============================================
   Header 页头
   ============================================ */

.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--accent-color), var(--accent-dark));
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1.125rem;
}

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

.nav a {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.9375rem;
  padding: 0.5rem 0;
  border-bottom: 2px solid transparent;
  transition: all 0.2s ease;
}

.nav a:hover,
.nav a.active {
  color: var(--accent-color);
  border-bottom-color: var(--accent-color);
}

.search-box {
  position: relative;
}

.search-box input {
  width: 240px;
  padding: 0.5rem 1rem 0.5rem 2.5rem;
  border: 1px solid var(--border-color);
  border-radius: 20px;
  font-size: 0.875rem;
  background: var(--bg-secondary);
  transition: all 0.2s ease;
}

.search-box input:focus {
  outline: none;
  border-color: var(--accent-color);
  background: var(--bg-primary);
}

.search-box::before {
  content: "🔍";
  position: absolute;
  left: 0.75rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 0.875rem;
  opacity: 0.5;
}

/* ============================================
   Hero 区域
   ============================================ */

.hero {
  background: linear-gradient(135deg, var(--accent-light) 0%, var(--bg-primary) 100%);
  padding: 4rem 0;
  text-align: center;
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.hero-subtitle {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 2rem;
}

.hero-cta {
  display: flex;
  gap: 1rem;
  justify-content: center;
}

/* ============================================
   统计数据
   ============================================ */

.stats-section {
  padding: 3rem 0;
  background: var(--bg-primary);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.stat-card {
  text-align: center;
  padding: 2rem;
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.stat-number {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--accent-color);
  line-height: 1;
}

.stat-label {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  margin-top: 0.5rem;
}

/* ============================================
   内容区域
   ============================================ */

.content-section {
  padding: 3rem 0;
}

.content-section:nth-child(even) {
  background: var(--bg-secondary);
}

/* ============================================
   课程卡片
   ============================================ */

.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

.course-card {
  background: var(--bg-primary);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  overflow: hidden;
  transition: box-shadow 0.2s ease, transform 0.2s ease;
}

.course-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.course-header {
  padding: 1.25rem;
  border-bottom: 1px solid var(--border-color);
}

.course-title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.course-meta {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.course-body {
  padding: 1.25rem;
}

.course-progress {
  margin-bottom: 1rem;
}

.course-status {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.status-completed::before {
  content: "✓";
  color: var(--accent-color);
  font-weight: bold;
}

.status-reading::before {
  content: "▶";
  color: var(--accent-color);
}

/* ============================================
   文章列表
   ============================================ */

.article-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.article-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
  background: var(--bg-primary);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  transition: all 0.2s ease;
}

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

.article-number {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent-light);
  color: var(--accent-dark);
  font-weight: 600;
  border-radius: var(--radius-sm);
  flex-shrink: 0;
}

.article-info {
  flex: 1;
}

.article-title {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

.article-meta {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

/* ============================================
   三栏文章布局
   ============================================ */

.articles-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.article-column {
  background: var(--bg-primary);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  overflow: hidden;
}

.column-header {
  padding: 1rem 1.25rem;
  background: var(--bg-tertiary);
  border-bottom: 1px solid var(--border-color);
}

.column-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
}

.column-list {
  padding: 0.75rem;
}

.column-item {
  display: block;
  padding: 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.9375rem;
  color: var(--text-secondary);
  transition: all 0.2s ease;
}

.column-item:hover {
  background: var(--accent-light);
  color: var(--accent-dark);
}

.column-item::before {
  content: "•";
  margin-right: 0.5rem;
  color: var(--accent-color);
}

/* ============================================
   分类页筛选
   ============================================ */

.filter-bar {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

.filter-btn {
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
  border-radius: 20px;
  border: 1px solid var(--border-color);
  background: var(--bg-primary);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s ease;
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--accent-color);
  border-color: var(--accent-color);
  color: white;
}

/* ============================================
   分类头部
   ============================================ */

.category-header {
  padding: 2rem 0;
  text-align: center;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
}

.category-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.category-desc {
  font-size: 1rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

.category-stats {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-top: 1.5rem;
}

.category-stat {
  text-align: center;
}

.category-stat-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent-color);
}

.category-stat-label {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

/* ============================================
   文章详情页
   ============================================ */

.article-header {
  padding: 2rem 0;
  text-align: center;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
}

.article-page-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1rem;
  line-height: 1.3;
}

.article-meta-bar {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.article-meta-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9375rem;
  color: var(--text-secondary);
}

.article-content-wrapper {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 2rem;
  padding: 2rem 0;
}

.article-main {
  background: var(--bg-primary);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  padding: 2rem;
}

.article-content {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--text-primary);
}

.article-content h2 {
  font-size: 1.5rem;
  font-weight: 600;
  margin: 2rem 0 1rem;
  color: var(--text-primary);
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--accent-light);
}

.article-content h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 1.5rem 0 0.75rem;
  color: var(--text-primary);
}

.article-content p {
  margin-bottom: 1rem;
  color: var(--text-secondary);
}

.article-content ul,
.article-content ol {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

.article-content ul li {
  list-style: disc;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
}

.article-content ol li {
  list-style: decimal;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
}

.article-sidebar {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.sidebar-card {
  background: var(--bg-primary);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  padding: 1.25rem;
}

.sidebar-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-color);
}

.progress-card {
  text-align: center;
}

.progress-status {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.progress-percentage {
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent-color);
  margin-top: 0.5rem;
}

.toc-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.toc-item {
  font-size: 0.875rem;
  color: var(--text-secondary);
  padding: 0.5rem;
  border-radius: var(--radius-sm);
  transition: all 0.2s ease;
}

.toc-item:hover {
  background: var(--accent-light);
  color: var(--accent-dark);
}

.toc-item.active {
  background: var(--accent-light);
  color: var(--accent-dark);
  font-weight: 500;
}

.related-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.related-item {
  display: flex;
  gap: 0.75rem;
  padding: 0.75rem;
  border-radius: var(--radius-sm);
  transition: all 0.2s ease;
}

.related-item:hover {
  background: var(--bg-secondary);
}

.related-thumb {
  width: 60px;
  height: 60px;
  background: var(--accent-light);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  flex-shrink: 0;
}

.related-info {
  flex: 1;
}

.related-title {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
  line-height: 1.4;
}

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

/* ============================================
   404 页面
   ============================================ */

.error-page {
  min-height: calc(100vh - var(--header-height) - 200px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 3rem 0;
}

.error-content {
  text-align: center;
  max-width: 500px;
}

.error-code {
  font-size: 8rem;
  font-weight: 700;
  color: var(--accent-color);
  line-height: 1;
  opacity: 0.3;
}

.error-title {
  font-size: 1.75rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.error-desc {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

.error-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
}

/* ============================================
   Footer 页脚
   ============================================ */

.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 3rem 0 2rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-brand {
  max-width: 300px;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.footer-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.footer-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-links a {
  font-size: 0.875rem;
  color: var(--text-secondary);
  transition: color 0.2s ease;
}

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

.footer-bottom {
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
  text-align: center;
  font-size: 0.875rem;
  color: var(--text-muted);
}

/* ============================================
   响应式设计
   ============================================ */

@media (max-width: 1024px) {
  .article-content-wrapper {
    grid-template-columns: 1fr;
  }

  .article-sidebar {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
  }

  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 56px;
  }

  .header .container {
    flex-wrap: wrap;
    height: auto;
    padding: 0.75rem 20px;
  }

  .nav {
    order: 3;
    width: 100%;
    gap: 1rem;
    margin-top: 0.75rem;
    padding-top: 0.75rem;
    border-top: 1px solid var(--border-color);
  }

  .nav a {
    font-size: 0.875rem;
  }

  .search-box {
    order: 2;
  }

  .search-box input {
    width: 160px;
  }

  .hero {
    padding: 2.5rem 0;
  }

  .hero-title {
    font-size: 1.75rem;
  }

  .hero-subtitle {
    font-size: 1rem;
  }

  .hero-cta {
    flex-direction: column;
    align-items: center;
  }

  .stats-grid {
    grid-template-columns: 1fr;
  }

  .articles-grid {
    grid-template-columns: 1fr;
  }

  .course-grid {
    grid-template-columns: 1fr;
  }

  .category-stats {
    flex-direction: column;
    gap: 1rem;
  }

  .article-page-title {
    font-size: 1.5rem;
  }

  .article-meta-bar {
    flex-direction: column;
    gap: 0.5rem;
  }

  .article-sidebar {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .footer-brand {
    max-width: 100%;
  }

  .footer-logo {
    justify-content: center;
  }

  .error-code {
    font-size: 5rem;
  }

  .error-actions {
    flex-direction: column;
    align-items: center;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  .section-title {
    font-size: 1.25rem;
  }

  .article-main {
    padding: 1.25rem;
  }

  .article-content h2 {
    font-size: 1.25rem;
  }

  .article-content h3 {
    font-size: 1.125rem;
  }
}