/* ========================================
   耳机知识库 - 全局样式
   www.erjiluntan.cn
   ======================================== */

/* CSS 变量 */
:root {
  --accent-color: #7c6a46;
  --accent-light: #9a8660;
  --accent-dark: #5c4f35;
  --bg-primary: #f8f6f3;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f0ede8;
  --text-primary: #2d2d2d;
  --text-secondary: #5a5a5a;
  --text-muted: #888888;
  --border-color: #e0dcd5;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --max-width: 1200px;
  --header-height: 64px;
}

/* 重置 */
*, *::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: var(--bg-primary);
}

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-secondary);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
}

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

.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: var(--accent-color);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1rem;
}

.nav {
  display: flex;
  gap: 28px;
}

.nav a {
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
}

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

.search-box {
  position: relative;
  width: 280px;
}

.search-box input {
  width: 100%;
  padding: 10px 16px 10px 40px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-primary);
  font-size: 0.9rem;
  transition: all 0.2s;
}

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

.search-box::before {
  content: "🔍";
  position: absolute;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 0.9rem;
  opacity: 0.5;
}

/* ========================================
   页脚
   ======================================== */
.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 40px 0 24px;
  margin-top: 60px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 32px;
}

.footer-brand p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-top: 12px;
  line-height: 1.7;
}

.footer-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 16px;
}

.footer-links li {
  margin-bottom: 10px;
}

.footer-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

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

.footer-bottom {
  border-top: 1px solid var(--border-color);
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* ========================================
   Hero 区域
   ======================================== */
.hero {
  background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
  padding: 60px 0;
  text-align: center;
  border-bottom: 1px solid var(--border-color);
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 12px;
}

.hero-desc {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 32px;
}

.hero-search {
  max-width: 600px;
  margin: 0 auto;
  position: relative;
}

.hero-search input {
  width: 100%;
  padding: 18px 24px 18px 56px;
  border: 2px solid var(--border-color);
  border-radius: var(--radius-lg);
  font-size: 1.1rem;
  background: var(--bg-secondary);
  transition: all 0.2s;
}

.hero-search input:focus {
  outline: none;
  border-color: var(--accent-color);
  box-shadow: var(--shadow-md);
}

.hero-search::before {
  content: "🔍";
  position: absolute;
  left: 22px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.2rem;
  opacity: 0.5;
}

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

.breadcrumb-inner {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9rem;
  color: var(--text-muted);
}

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

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

.breadcrumb-sep {
  opacity: 0.5;
}

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

/* ========================================
   卡片组件
   ======================================== */
.card {
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  padding: 20px;
  transition: all 0.2s;
}

.card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--accent-light);
}

.card-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.card-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.card-meta {
  display: flex;
  gap: 16px;
  margin-top: 12px;
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ========================================
   分类标签
   ======================================== */
.category-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.category-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 18px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: all 0.2s;
}

.category-tag:hover {
  background: var(--accent-color);
  border-color: var(--accent-color);
  color: white;
}

.category-tag .count {
  background: var(--bg-tertiary);
  color: var(--text-muted);
  padding: 2px 8px;
  border-radius: 12px;
  font-size: 0.75rem;
}

.category-tag:hover .count {
  background: rgba(255,255,255,0.2);
  color: white;
}

/* ========================================
   区块标题
   ======================================== */
.section {
  padding: 40px 0;
}

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
}

.section-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 10px;
}

.section-title::before {
  content: "";
  width: 4px;
  height: 20px;
  background: var(--accent-color);
  border-radius: 2px;
}

.section-more {
  font-size: 0.9rem;
  color: var(--accent-color);
}

/* ========================================
   内容网格
   ======================================== */
.content-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}

.content-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.content-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 16px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: all 0.2s;
}

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

.content-item-icon {
  width: 40px;
  height: 40px;
  background: var(--bg-tertiary);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.content-item-body {
  flex: 1;
  min-width: 0;
}

.content-item-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 4px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.content-item-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.content-item-meta {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 8px;
}

/* ========================================
   三栏布局
   ======================================== */
.three-columns {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.column-box {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px;
}

.column-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 16px;
}

.column-list li {
  padding: 10px 0;
  border-bottom: 1px dashed var(--border-color);
}

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

.column-list a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  gap: 8px;
}

.column-list a::before {
  content: "•";
  color: var(--accent-color);
}

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

/* ========================================
   文章页布局
   ======================================== */
.article-layout {
  display: grid;
  grid-template-columns: 240px 1fr 280px;
  gap: 32px;
  padding: 32px 0;
}

.sidebar-left,
.sidebar-right {
  position: sticky;
  top: 84px;
  height: fit-content;
}

.sidebar-box {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px;
  margin-bottom: 20px;
}

.sidebar-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.toc-list li {
  margin-bottom: 8px;
}

.toc-list a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  display: block;
  padding: 6px 0;
  border-left: 2px solid transparent;
  padding-left: 12px;
  margin-left: -12px;
}

.toc-list a:hover,
.toc-list a.active {
  color: var(--accent-color);
  border-left-color: var(--accent-color);
}

.toc-list.level-2 a {
  padding-left: 24px;
  font-size: 0.85rem;
}

/* ========================================
   文章正文
   ======================================== */
.article-main {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 32px;
}

.article-header {
  margin-bottom: 32px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-color);
}

.article-title {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.4;
  margin-bottom: 16px;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 20px;
  color: var(--text-muted);
  font-size: 0.9rem;
}

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

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

.article-body h2 {
  font-size: 1.4rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 32px 0 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-color);
}

.article-body h3 {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 24px 0 12px;
}

.article-body p {
  margin-bottom: 16px;
}

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

.article-body ul li {
  list-style: disc;
  margin-bottom: 8px;
}

.article-body ol li {
  list-style: decimal;
  margin-bottom: 8px;
}

.article-body strong {
  font-weight: 600;
  color: var(--accent-dark);
}

/* 信息框 */
.info-box {
  background: var(--bg-tertiary);
  border-left: 4px solid var(--accent-color);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 20px;
  margin: 24px 0;
}

.info-box-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 12px;
}

.info-box-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

.info-box-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.info-box-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
}

.info-box-value {
  font-size: 0.95rem;
  color: var(--text-primary);
  font-weight: 500;
}

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

.category-header-inner {
  display: flex;
  align-items: flex-start;
  gap: 24px;
}

.category-icon {
  width: 64px;
  height: 64px;
  background: var(--accent-color);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  color: white;
  flex-shrink: 0;
}

.category-info h1 {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.category-info p {
  color: var(--text-secondary);
  font-size: 1rem;
  line-height: 1.6;
  max-width: 600px;
}

.category-stats {
  display: flex;
  gap: 24px;
  margin-top: 16px;
}

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

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

.category-stat-label {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ========================================
   子分类
   ======================================== */
.subcategories {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 20px;
}

.subcategory-tag {
  padding: 8px 16px;
  background: var(--bg-tertiary);
  border-radius: 20px;
  font-size: 0.85rem;
  color: var(--text-secondary);
  transition: all 0.2s;
}

.subcategory-tag:hover {
  background: var(--accent-color);
  color: white;
}

/* ========================================
   推荐文章行
   ======================================== */
.related-row {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  margin-bottom: 24px;
}

.related-row-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 12px;
}

.related-row-list {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.related-row-list a {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

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

/* ========================================
   404 页面
   ======================================== */
.error-page {
  min-height: calc(100vh - var(--header-height) - 200px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px 20px;
}

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

.error-code {
  font-size: 8rem;
  font-weight: 700;
  color: var(--accent-color);
  line-height: 1;
  opacity: 0.8;
}

.error-title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 20px 0 12px;
}

.error-desc {
  color: var(--text-secondary);
  margin-bottom: 28px;
}

.error-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  font-weight: 500;
  transition: all 0.2s;
}

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

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

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: var(--border-color);
  color: var(--text-primary);
}

/* ========================================
   响应式设计
   ======================================== */
@media (max-width: 1024px) {
  .article-layout {
    grid-template-columns: 1fr;
  }

  .sidebar-left,
  .sidebar-right {
    position: static;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
  }

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

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

  .header-inner {
    flex-wrap: wrap;
    height: auto;
    padding: 12px 0;
    gap: 12px;
  }

  .nav {
    order: 3;
    width: 100%;
    justify-content: center;
    gap: 20px;
    padding-top: 8px;
    border-top: 1px solid var(--border-color);
  }

  .search-box {
    width: 200px;
  }

  .hero {
    padding: 40px 0;
  }

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

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

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 24px;
  }

  .category-header-inner {
    flex-direction: column;
    text-align: center;
  }

  .category-icon {
    margin: 0 auto;
  }

  .category-stats {
    justify-content: center;
  }

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

  .sidebar-left,
  .sidebar-right {
    grid-template-columns: 1fr;
  }

  .article-main {
    padding: 20px;
  }

  .article-title {
    font-size: 1.4rem;
  }

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

@media (max-width: 480px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }

  .error-actions {
    flex-direction: column;
  }

  .btn {
    justify-content: center;
  }
}