/* 信息技术课堂 - 样式文件 */
/* 查询关键词: 信息技术课堂 www.yqqsgl.cn 信息课堂资源 数字教学课件 编程入门教程 */

/* ===== CSS 变量 ===== */
:root {
  --accent-color: #20c997;
  --accent-dark: #1ba87e;
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-dark: #212529;
  --text-primary: #212529;
  --text-secondary: #6c757d;
  --text-light: #ffffff;
  --border-color: #dee2e6;
  --shadow: 0 2px 8px rgba(0,0,0,0.1);
  --shadow-hover: 0 4px 16px rgba(0,0,0,0.15);
  --radius: 8px;
  --radius-lg: 12px;
  --max-width: 1200px;
  --header-height: 64px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-secondary);
}

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

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

ul {
  list-style: none;
}

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

/* ===== 布局容器 ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* ===== 页头 ===== */
.header {
  background: var(--bg-primary);
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
}

.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  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);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-light);
  font-size: 1rem;
}

.nav {
  display: flex;
  gap: 32px;
}

.nav a {
  color: var(--text-primary);
  font-weight: 500;
  padding: 8px 0;
  border-bottom: 2px solid transparent;
}

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

.search-box {
  display: flex;
  align-items: center;
  background: var(--bg-secondary);
  border-radius: 20px;
  padding: 6px 16px;
  gap: 8px;
}

.search-box input {
  border: none;
  background: none;
  outline: none;
  width: 160px;
  font-size: 0.875rem;
}

/* ===== 面包屑 ===== */
.breadcrumb {
  background: var(--bg-primary);
  padding: 16px 0;
  border-bottom: 1px solid var(--border-color);
  font-size: 0.875rem;
}

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

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

.breadcrumb span {
  color: var(--text-secondary);
  margin: 0 8px;
}

.breadcrumb strong {
  color: var(--text-primary);
  font-weight: 500;
}

/* ===== Hero 区域 ===== */
.hero {
  background: linear-gradient(135deg, var(--accent-color), var(--accent-dark));
  color: var(--text-light);
  padding: 60px 0;
  text-align: center;
}

.hero h1 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.hero p {
  font-size: 1.125rem;
  opacity: 0.9;
  max-width: 600px;
  margin: 0 auto;
}

/* ===== 统计卡片 ===== */
.stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 40px;
}

.stat-card {
  background: rgba(255,255,255,0.15);
  backdrop-filter: blur(10px);
  border-radius: var(--radius-lg);
  padding: 24px;
  text-align: center;
}

.stat-number {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.stat-label {
  font-size: 0.875rem;
  opacity: 0.9;
}

/* ===== 内容区域 ===== */
.section {
  padding: 48px 0;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 24px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.section-title::before {
  content: '';
  width: 4px;
  height: 24px;
  background: var(--accent-color);
  border-radius: 2px;
}

/* ===== 卡片网格 ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.card-grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.card-grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

/* ===== 课程卡片 ===== */
.course-card {
  background: var(--bg-primary);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: transform 0.2s, box-shadow 0.2s;
}

.course-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.course-cover {
  height: 160px;
  background: linear-gradient(135deg, var(--accent-color), var(--accent-dark));
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-light);
  font-size: 3rem;
}

.course-body {
  padding: 20px;
}

.course-category {
  font-size: 0.75rem;
  color: var(--accent-color);
  font-weight: 600;
  text-transform: uppercase;
  margin-bottom: 8px;
}

.course-title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text-primary);
}

.course-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: 16px;
  line-height: 1.5;
}

.course-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

/* ===== 进度条 ===== */
.progress-bar {
  background: var(--bg-secondary);
  height: 8px;
  border-radius: 4px;
  overflow: hidden;
  margin: 12px 0;
}

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

.progress-text {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

/* ===== 列表卡片 ===== */
.list-card {
  background: var(--bg-primary);
  border-radius: var(--radius);
  padding: 16px 20px;
  box-shadow: var(--shadow);
}

.list-card li {
  padding: 12px 0;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  gap: 12px;
}

.list-card li:last-child {
  border-bottom: none;
}

.list-card li::before {
  content: '';
  width: 6px;
  height: 6px;
  background: var(--accent-color);
  border-radius: 50%;
}

.list-card a {
  color: var(--text-primary);
  flex: 1;
}

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

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

/* ===== 分类页样式 ===== */
.category-header {
  background: var(--bg-primary);
  padding: 40px 0;
  border-bottom: 1px solid var(--border-color);
}

.category-header h1 {
  font-size: 2rem;
  margin-bottom: 8px;
}

.category-header p {
  color: var(--text-secondary);
}

.filter-tabs {
  display: flex;
  gap: 8px;
  margin-top: 24px;
}

.filter-tab {
  padding: 8px 20px;
  border-radius: 20px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  background: var(--bg-secondary);
  border: none;
  cursor: pointer;
  transition: all 0.2s;
}

.filter-tab:hover,
.filter-tab.active {
  background: var(--accent-color);
  color: var(--text-light);
}

/* ===== 文章页样式 ===== */
.article-header {
  background: var(--bg-primary);
  padding: 40px 0;
  border-bottom: 1px solid var(--border-color);
}

.article-title {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 16px;
  line-height: 1.3;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 20px;
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.article-meta span {
  display: flex;
  align-items: center;
  gap: 6px;
}

.article-content {
  background: var(--bg-primary);
  padding: 40px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  margin: 24px 0;
}

.article-content h2 {
  font-size: 1.5rem;
  margin: 32px 0 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--border-color);
}

.article-content h3 {
  font-size: 1.25rem;
  margin: 24px 0 12px;
  color: var(--accent-dark);
}

.article-content p {
  margin-bottom: 16px;
  line-height: 1.8;
}

.article-content ul,
.article-content ol {
  margin: 16px 0;
  padding-left: 24px;
}

.article-content li {
  margin: 8px 0;
}

.article-content pre {
  background: var(--bg-dark);
  color: var(--text-light);
  padding: 20px;
  border-radius: var(--radius);
  overflow-x: auto;
  font-family: "Consolas", "Monaco", monospace;
  font-size: 0.875rem;
  line-height: 1.6;
  margin: 20px 0;
}

.article-content code {
  background: var(--bg-secondary);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: "Consolas", "Monaco", monospace;
  font-size: 0.875em;
  color: var(--accent-dark);
}

.article-content pre code {
  background: none;
  padding: 0;
  color: inherit;
}

/* ===== 代码演示框 ===== */
.code-demo {
  background: var(--bg-dark);
  border-radius: var(--radius);
  overflow: hidden;
  margin: 24px 0;
}

.code-demo-header {
  background: rgba(255,255,255,0.1);
  padding: 12px 20px;
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.875rem;
  color: var(--text-light);
}

.code-demo-header span {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}

.code-demo-header .dot-red { background: #ff5f56; }
.code-demo-header .dot-yellow { background: #ffbd2e; }
.code-demo-header .dot-green { background: #27c93f; }

.code-demo pre {
  margin: 0;
  padding: 20px;
  background: none;
}

/* ===== 章节导航 ===== */
.chapter-nav {
  background: var(--bg-primary);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow);
  position: sticky;
  top: 80px;
}

.chapter-nav h3 {
  font-size: 1rem;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-color);
}

.chapter-nav li {
  padding: 10px 0;
  border-bottom: 1px solid var(--border-color);
}

.chapter-nav li:last-child {
  border-bottom: none;
}

.chapter-nav a {
  color: var(--text-secondary);
  font-size: 0.875rem;
  display: block;
}

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

.chapter-nav .chapter-num {
  color: var(--accent-color);
  font-weight: 600;
  margin-right: 8px;
}

/* ===== 练习题框 ===== */
.exercise-box {
  background: linear-gradient(135deg, #fff9e6, #fff3cd);
  border-left: 4px solid #ffc107;
  border-radius: var(--radius);
  padding: 20px;
  margin: 24px 0;
}

.exercise-box h4 {
  color: #856404;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.exercise-box p {
  color: #856404;
  margin-bottom: 12px;
}

.exercise-box ol {
  color: #856404;
  padding-left: 20px;
}

.exercise-box li {
  margin: 8px 0;
}

/* ===== 两栏布局 ===== */
.two-column {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 24px;
}

/* ===== 标签 ===== */
.tag {
  display: inline-block;
  padding: 4px 12px;
  background: var(--bg-secondary);
  border-radius: 12px;
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-right: 8px;
}

.tag-primary {
  background: var(--accent-color);
  color: var(--text-light);
}

/* ===== 404页面 ===== */
.error-page {
  min-height: calc(100vh - var(--header-height) - 200px);
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 60px 20px;
}

.error-code {
  font-size: 8rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--accent-color), var(--accent-dark));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1;
  margin-bottom: 24px;
}

.error-title {
  font-size: 1.5rem;
  margin-bottom: 16px;
}

.error-desc {
  color: var(--text-secondary);
  margin-bottom: 32px;
}

.btn {
  display: inline-block;
  padding: 12px 32px;
  background: var(--accent-color);
  color: var(--text-light);
  border-radius: 24px;
  font-weight: 500;
  transition: background 0.2s;
}

.btn:hover {
  background: var(--accent-dark);
  color: var(--text-light);
}

/* ===== 页脚 ===== */
.footer {
  background: var(--bg-dark);
  color: var(--text-light);
  padding: 48px 0 24px;
  margin-top: 48px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand p {
  color: rgba(255,255,255,0.7);
  margin-top: 16px;
  font-size: 0.875rem;
}

.footer h4 {
  font-size: 1rem;
  margin-bottom: 20px;
}

.footer li {
  margin: 12px 0;
}

.footer a {
  color: rgba(255,255,255,0.7);
  font-size: 0.875rem;
}

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

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 24px;
  text-align: center;
  color: rgba(255,255,255,0.5);
  font-size: 0.875rem;
}

/* ===== 响应式设计 ===== */
@media (max-width: 992px) {
  .card-grid,
  .card-grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .two-column {
    grid-template-columns: 1fr;
  }

  .chapter-nav {
    position: static;
  }
}

@media (max-width: 768px) {
  .nav {
    display: none;
  }

  .search-box {
    display: none;
  }

  .hero h1 {
    font-size: 1.75rem;
  }

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

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

  .filter-tabs {
    flex-wrap: wrap;
  }

  .article-content {
    padding: 24px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

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

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

  .section {
    padding: 32px 0;
  }

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