/* =========================================================
   51吃瓜在线 · 全站样式表
   资讯内容站 · 简洁目录风
   版本：1.0
   ========================================================= */

/* =========================================================
   Base —— 变量、重置、全局基础
   ========================================================= */
:root {
  --color-bg: #f5f5f5;
  --color-text: #333333;
  --color-primary: #007bff;
  --color-primary-dark: #0062cc;
  --color-white: #ffffff;
  --color-gray-light: #e9ecef;
  --color-gray-border: #dee2e6;
  --color-gray-muted: #6c757d;
  --color-gray-dark: #495057;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", sans-serif;

  --container-width: 1200px;
  --container-padding: 24px;
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;

  --header-height: 68px;
  --transition-speed: 0.2s;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

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

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

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

ul,
ol {
  list-style: none;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  line-height: 1.3;
  font-weight: 700;
  color: var(--color-text);
}

h1 {
  font-size: 2rem;
}

h2 {
  font-size: 1.5rem;
}

h3 {
  font-size: 1.125rem;
}

p {
  margin-bottom: 1rem;
}

time {
  color: var(--color-gray-muted);
  font-size: 0.875rem;
}

figure {
  margin: 0;
}

/* =========================================================
   Layout —— 全站骨架、容器、页头、页脚
   ========================================================= */
.site-body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.site-header {
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-gray-light);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
  height: var(--header-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand-link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  flex-shrink: 0;
}

.brand-name {
  font-size: 1.375rem;
  font-weight: 800;
  color: var(--color-text);
  letter-spacing: 0.01em;
}

.brand-slogan {
  font-size: 0.8125rem;
  color: var(--color-gray-muted);
  white-space: nowrap;
}

.site-nav .nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.site-nav .nav-list a {
  display: block;
  padding: 8px 16px;
  font-size: 0.9375rem;
  color: var(--color-text);
  border-radius: var(--radius-sm);
  line-height: 1.4;
}

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

.site-nav .nav-list a.is-current {
  color: var(--color-primary);
  font-weight: 600;
  background-color: rgba(0, 123, 255, 0.08);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 10px;
  background: transparent;
  border: 1px solid var(--color-gray-light);
  border-radius: var(--radius-sm);
  cursor: pointer;
  flex-shrink: 0;
}

.nav-toggle-bar {
  display: block;
  width: 100%;
  height: 2px;
  background-color: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition-speed) ease,
    opacity var(--transition-speed) ease;
}

.site-main {
  flex: 1 0 auto;
}

.site-home .site-main,
.site-inner .site-main {
  width: 100%;
}

.home-main {
  padding-bottom: 48px;
}

.inner-main {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 32px var(--container-padding) 56px;
  width: 100%;
}

/* 面包屑 */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.875rem;
  color: var(--color-gray-muted);
  margin-bottom: 24px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--color-gray-light);
}

.breadcrumb a {
  color: var(--color-gray-muted);
}

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

.breadcrumb-sep {
  color: var(--color-gray-muted);
}

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

/* 页面标题区 */
.page-header {
  margin-bottom: 32px;
}

.page-title {
  font-size: 1.875rem;
  font-weight: 800;
  margin-bottom: 12px;
  line-height: 1.3;
}

.page-description {
  font-size: 1rem;
  color: var(--color-gray-muted);
  max-width: 720px;
  margin-bottom: 0;
}

/* 页脚 */
.site-footer {
  background-color: var(--color-white);
  border-top: 1px solid var(--color-gray-light);
  margin-top: auto;
}

.footer-inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 40px var(--container-padding) 24px;
}

.footer-brand {
  margin-bottom: 24px;
}

.footer-brand-name {
  font-size: 1.125rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.footer-brand-desc {
  font-size: 0.875rem;
  color: var(--color-gray-muted);
  max-width: 480px;
  margin-bottom: 0;
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  padding: 24px 0;
  border-top: 1px solid var(--color-gray-light);
}

.footer-col h3 {
  font-size: 0.9375rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.footer-col ul li {
  margin-bottom: 8px;
}

.footer-col ul a {
  font-size: 0.875rem;
  color: var(--color-gray-muted);
}

.footer-col ul a:hover {
  color: var(--color-primary);
}

.footer-bottom {
  padding-top: 16px;
  border-top: 1px solid var(--color-gray-light);
}

.footer-bottom p {
  font-size: 0.8125rem;
  color: var(--color-gray-muted);
  margin-bottom: 0;
}

/* =========================================================
   Components —— 通用组件：按钮、区块、卡片
   ========================================================= */
.btn-primary,
.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 24px;
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  min-height: 44px;
  transition: background-color var(--transition-speed) ease,
    color var(--transition-speed) ease, border-color var(--transition-speed) ease;
}

.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-white);
  border: 1px solid var(--color-primary);
}

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

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

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

.section-block {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 40px var(--container-padding) 0;
}

.section-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 24px;
}

.section-head h2 {
  font-size: 1.375rem;
  font-weight: 700;
  margin-bottom: 0;
}

.section-more {
  font-size: 0.875rem;
  color: var(--color-primary);
  white-space: nowrap;
  flex-shrink: 0;
}

.section-more:hover {
  text-decoration: underline;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 24px;
}

/* =========================================================
   Components —— 首页首屏焦点区
   ========================================================= */
.hero-section {
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-gray-light);
}

.hero-section {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 48px var(--container-padding) 40px;
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 40px;
  align-items: center;
}

.hero-content {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 16px;
}

.hero-title {
  font-size: 2.125rem;
  font-weight: 800;
  line-height: 1.3;
  margin-bottom: 0;
}

.hero-desc {
  font-size: 1rem;
  color: var(--color-gray-muted);
  line-height: 1.8;
  margin-bottom: 0;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 8px;
}

.hero-figure {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: var(--color-gray-light);
}

.hero-figure img {
  width: 100%;
  height: 320px;
  object-fit: cover;
}

/* =========================================================
   Components —— 首页最新资讯列表
   ========================================================= */
.news-list {
  display: flex;
  flex-direction: column;
}

.news-item {
  display: flex;
  align-items: flex-start;
  gap: 20px;
  padding: 20px 0;
  border-bottom: 1px solid var(--color-gray-light);
}

.news-item:first-child {
  padding-top: 0;
}

.news-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.news-text {
  flex: 1;
}

.news-text h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin-bottom: 6px;
  line-height: 1.5;
}

.news-text h3 a {
  color: var(--color-text);
}

.news-text h3 a:hover {
  color: var(--color-primary);
}

.news-summary {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  line-height: 1.7;
  margin-bottom: 8px;
}

.news-date {
  display: block;
}

/* =========================================================
   Components —— 首页频道分类导航带
   ========================================================= */
.channel-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 16px;
}

.channel-tag {
  display: inline-block;
  padding: 8px 24px;
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-border);
  border-radius: var(--radius-md);
  font-size: 0.9375rem;
  color: var(--color-text);
  transition: all var(--transition-speed) ease;
}

.channel-tag:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background-color: rgba(0, 123, 255, 0.04);
}

.channel-desc {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  margin-bottom: 0;
}

/* =========================================================
   Components —— 专题卡片
   ========================================================= */
.topics-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.topic-card {
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-light);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: box-shadow var(--transition-speed) ease,
    border-color var(--transition-speed) ease;
}

.topic-card:hover {
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
  border-color: var(--color-gray-border);
}

.topic-figure {
  background-color: var(--color-gray-light);
}

.topic-figure img {
  width: 100%;
  height: 200px;
  object-fit: cover;
}

.topic-info {
  padding: 20px;
}

.topic-info h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.topic-info h3 a {
  color: var(--color-text);
}

.topic-info h3 a:hover {
  color: var(--color-primary);
}

.topic-info p {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  line-height: 1.7;
  margin-bottom: 0;
}

/* =========================================================
   Components —— 首页编辑推荐
   ========================================================= */
.picks-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.pick-item {
  display: flex;
  align-items: flex-start;
  gap: 20px;
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-light);
  border-radius: var(--radius-md);
  padding: 20px;
}

.pick-index {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--color-primary);
  line-height: 1;
  min-width: 36px;
  flex-shrink: 0;
  padding-top: 2px;
}

.pick-content h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin-bottom: 6px;
}

.pick-content h3 a {
  color: var(--color-text);
}

.pick-content h3 a:hover {
  color: var(--color-primary);
}

.pick-reason {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  margin-bottom: 0;
}

/* =========================================================
   Components —— 信息来源与反馈
   ========================================================= */
.source-content p {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  line-height: 1.8;
  margin-bottom: 12px;
}

.feedback-link {
  display: inline-block;
  font-size: 0.9375rem;
  font-weight: 500;
  margin-top: 4px;
}

/* =========================================================
   Pages —— 频道分类页
   ========================================================= */
.channel-list-section {
  margin-bottom: 40px;
}

.channel-list-section .section-intro {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  margin-bottom: 24px;
}

.channel-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-light);
  border-radius: var(--radius-lg);
  padding: 24px;
  margin-bottom: 16px;
}

.channel-item:last-child {
  margin-bottom: 0;
}

.channel-info {
  flex: 1;
}

.channel-info h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.channel-info p {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  line-height: 1.7;
  margin-bottom: 12px;
}

.channel-info a {
  font-size: 0.875rem;
  font-weight: 500;
}

.channel-figure {
  width: 160px;
  flex-shrink: 0;
  border-radius: var(--radius-md);
  overflow: hidden;
  background-color: var(--color-gray-light);
}

.channel-figure img {
  width: 100%;
  height: 110px;
  object-fit: cover;
}

.channel-guide-section {
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-light);
  border-radius: var(--radius-lg);
  padding: 24px;
  margin-bottom: 40px;
}

.channel-guide-section h2 {
  font-size: 1.25rem;
  margin-bottom: 12px;
}

.channel-guide-section > p {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  margin-bottom: 16px;
}

.guide-list {
  margin-bottom: 16px;
}

.guide-list li {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  padding: 6px 0;
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
}

.guide-list strong {
  color: var(--color-text);
  font-weight: 600;
  flex-shrink: 0;
}

.channel-guide-section > p:last-child {
  margin-bottom: 0;
}

.channel-hot-section {
  margin-bottom: 40px;
}

.hot-block {
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-light);
  border-radius: var(--radius-md);
  padding: 20px;
  margin-bottom: 16px;
}

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

.hot-block h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--color-gray-light);
}

.hot-list li {
  padding: 8px 0;
  border-bottom: 1px solid var(--color-gray-light);
}

.hot-list li:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.hot-list a {
  font-size: 0.9375rem;
  color: var(--color-text);
  line-height: 1.5;
}

.hot-list a:hover {
  color: var(--color-primary);
}

.related-links-section {
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-light);
  border-radius: var(--radius-lg);
  padding: 24px;
}

.related-links-section h2 {
  font-size: 1.25rem;
  margin-bottom: 12px;
}

.related-links-section > p {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  margin-bottom: 16px;
}

.related-links {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px 24px;
}

.related-links a {
  display: inline-block;
  padding: 6px 0;
  font-size: 0.9375rem;
  color: var(--color-text);
}

.related-links a:hover {
  color: var(--color-primary);
}

/* =========================================================
   Pages —— 内容专题页
   ========================================================= */
.topic-grid {
  margin-bottom: 40px;
}

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

.topic-cards .topic-card {
  display: flex;
  flex-direction: column;
}

.topic-cards .topic-figure img {
  height: 180px;
}

.topic-card-title {
  font-size: 1.125rem;
  font-weight: 600;
  margin: 16px 20px 8px;
}

.topic-card-desc {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  line-height: 1.7;
  margin: 0 20px 16px;
  flex: 1;
}

.topic-card-link {
  display: inline-block;
  font-size: 0.875rem;
  font-weight: 500;
  margin: 0 20px 20px;
}

.topic-intro {
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-light);
  border-radius: var(--radius-lg);
  padding: 24px;
  margin-bottom: 40px;
}

.topic-intro .section-title {
  font-size: 1.25rem;
  margin-bottom: 12px;
}

.topic-intro p {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  line-height: 1.8;
  margin-bottom: 12px;
}

.topic-intro p:last-child {
  margin-bottom: 0;
}

.topic-articles {
  margin-bottom: 40px;
}

.article-link-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.article-link-item {
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-light);
  border-radius: var(--radius-md);
  padding: 20px;
}

.article-link-title {
  font-size: 1.0625rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.article-link-title a {
  color: var(--color-text);
}

.article-link-title a:hover {
  color: var(--color-primary);
}

.article-link-item p {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  line-height: 1.7;
  margin-bottom: 0;
}

.source-feedback {
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-light);
  border-radius: var(--radius-lg);
  padding: 24px;
}

.source-feedback .section-title {
  font-size: 1.25rem;
  margin-bottom: 12px;
}

.source-feedback p {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  line-height: 1.8;
  margin-bottom: 8px;
}

.source-feedback p:last-child {
  margin-bottom: 0;
}

/* =========================================================
   Pages —— 热点解读文章页
   ========================================================= */
.content-section {
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-light);
  border-radius: var(--radius-lg);
  padding: 28px;
  margin-bottom: 24px;
}

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

.content-section h2 {
  font-size: 1.375rem;
  font-weight: 700;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--color-gray-light);
}

.content-section p {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  line-height: 1.8;
  margin-bottom: 16px;
}

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

.content-media {
  background-color: var(--color-gray-light);
  border-radius: var(--radius-md);
  overflow: hidden;
  margin-bottom: 16px;
}

.content-media-inline {
  max-width: 640px;
}

.content-media-inline img {
  width: 100%;
  height: 280px;
  object-fit: cover;
}

.content-media-inline figcaption {
  padding: 12px 16px;
  font-size: 0.8125rem;
  color: var(--color-gray-muted);
  background-color: var(--color-white);
  border-top: 1px solid var(--color-gray-light);
}

.analysis-list {
  margin-top: 16px;
}

.analysis-list li {
  padding: 16px 0;
  border-bottom: 1px solid var(--color-gray-light);
}

.analysis-list li:first-child {
  padding-top: 0;
}

.analysis-list li:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.analysis-list h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.analysis-list p {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  line-height: 1.7;
  margin-bottom: 0;
}

.related-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px 24px;
  margin-top: 8px;
}

.related-list a {
  display: inline-block;
  padding: 6px 0;
  font-size: 0.9375rem;
  color: var(--color-text);
}

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

/* =========================================================
   Pages —— 实用指南页
   ========================================================= */
.guide-intro {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 24px;
  align-items: center;
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-light);
  border-radius: var(--radius-lg);
  padding: 24px;
  margin-bottom: 32px;
}

.guide-media {
  border-radius: var(--radius-md);
  overflow: hidden;
  background-color: var(--color-gray-light);
}

.guide-figure img {
  width: 100%;
  height: 220px;
  object-fit: cover;
}

.guide-summary p {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  line-height: 1.8;
  margin-bottom: 0;
}

.guide-section {
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-light);
  border-radius: var(--radius-lg);
  padding: 28px;
  margin-bottom: 24px;
}

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

.guide-section > h2 {
  font-size: 1.375rem;
  font-weight: 700;
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--color-gray-light);
}

.guide-steps {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.guide-step {
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.step-number {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background-color: var(--color-primary);
  color: var(--color-white);
  font-size: 1.0625rem;
  font-weight: 700;
  border-radius: 50%;
  flex-shrink: 0;
  line-height: 1;
}

.step-content h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin-bottom: 6px;
}

.step-content p {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  line-height: 1.7;
  margin-bottom: 0;
}

.guide-related {
  margin-top: 20px;
  padding-top: 16px;
  border-top: 1px solid var(--color-gray-light);
}

.guide-related a {
  font-size: 0.9375rem;
  font-weight: 500;
}

.guide-feedback p {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  line-height: 1.8;
  margin-bottom: 8px;
}

.guide-feedback p:last-child {
  margin-bottom: 0;
}

/* =========================================================
   Pages —— 404 错误页
   ========================================================= */
.error-main {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 80px 24px;
  min-height: 60vh;
}

.error-section {
  text-align: center;
  max-width: 520px;
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-light);
  border-radius: var(--radius-lg);
  padding: 48px 40px;
}

.error-code {
  font-size: 4rem;
  font-weight: 800;
  color: var(--color-primary);
  line-height: 1;
  margin-bottom: 16px;
}

.error-section h1 {
  font-size: 1.5rem;
  margin-bottom: 12px;
}

.error-desc {
  font-size: 0.9375rem;
  color: var(--color-gray-muted);
  line-height: 1.7;
  margin-bottom: 24px;
}

.error-back {
  display: inline-block;
  padding: 10px 32px;
  background-color: var(--color-primary);
  color: var(--color-white);
  border-radius: var(--radius-md);
  font-size: 0.9375rem;
  font-weight: 600;
  min-height: 44px;
  line-height: 1.4;
}

.error-back:hover {
  background-color: var(--color-primary-dark);
  color: var(--color-white);
}

.error-help {
  font-size: 0.875rem;
  color: var(--color-gray-muted);
  margin-top: 24px;
  margin-bottom: 0;
}

.error-help a {
  margin: 0 8px;
}

/* =========================================================
   Responsive —— 响应式规则
   ========================================================= */
@media (max-width: 992px) {
  .hero-section {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .hero-figure img {
    height: 260px;
  }

  .guide-intro {
    grid-template-columns: 1fr;
  }

  .guide-figure img {
    height: 200px;
  }
}

@media (max-width: 768px) {
  :root {
    --container-padding: 16px;
  }

  .header-inner {
    height: auto;
    min-height: var(--header-height);
    flex-wrap: wrap;
    padding-top: 10px;
    padding-bottom: 10px;
    gap: 8px;
  }

  .brand-link {
    margin-right: auto;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    order: 3;
    width: 100%;
  }

  .site-nav .nav-list {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 0;
    border-top: 1px solid var(--color-gray-light);
  }

  .site-nav .nav-list.is-open {
    display: flex;
  }

  .site-nav .nav-list a {
    padding: 12px 8px;
    font-size: 1rem;
    border-radius: 0;
  }

  .hero-section {
    padding: 32px 16px 28px;
  }

  .hero-title {
    font-size: 1.625rem;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
    width: 100%;
  }

  .btn-primary,
  .btn-secondary {
    width: 100%;
  }

  .section-block {
    padding: 32px 16px 0;
  }

  .news-item {
    flex-direction: column;
    gap: 8px;
  }

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

  .pick-item {
    flex-direction: column;
    gap: 8px;
  }

  .channel-item {
    flex-direction: column;
    align-items: flex-start;
  }

  .channel-figure {
    width: 100%;
  }

  .channel-figure img {
    height: 160px;
  }

  .related-links {
    grid-template-columns: 1fr;
  }

  .topic-cards {
    grid-template-columns: 1fr;
  }

  .related-list {
    grid-template-columns: 1fr;
  }

  .footer-links {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .inner-main {
    padding: 24px 16px 40px;
  }

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

  .content-section,
  .guide-section,
  .source-feedback,
  .related-links-section,
  .channel-guide-section,
  .topic-intro {
    padding: 20px;
  }

  .content-media-inline img {
    height: 200px;
  }

  .error-main {
    padding: 48px 16px;
  }

  .error-section {
    padding: 32px 24px;
  }

  .error-code {
    font-size: 3rem;
  }
}

@media (max-width: 480px) {
  .brand-slogan {
    display: none;
  }

  .hero-figure img {
    height: 200px;
  }

  .topic-figure img {
    height: 180px;
  }

  .guide-figure img {
    height: 180px;
  }

  .topic-cards .topic-figure img {
    height: 160px;
  }

  .content-media-inline img {
    height: 180px;
  }

  .guide-step {
    flex-direction: column;
    gap: 8px;
  }

  .step-number {
    width: 32px;
    height: 32px;
    font-size: 0.9375rem;
  }
}