/* ==========================================================================
   base — 全局基础样式
   ========================================================================== */

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

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

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: #333333;
  background-color: #F5F7FA;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a {
  color: #4A90E2;
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: #FF8C42;
}

ul, ol {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  font-family: inherit;
  line-height: 1.4;
  color: #333333;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* ==========================================================================
   layout — 全站统一骨架布局
   ========================================================================== */

.site-body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.site-header {
  background-color: #ffffff;
  border-bottom: 1px solid #e8ecf0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

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

.brand a {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.brand-name {
  font-size: 22px;
  font-weight: 700;
  color: #FF8C42;
  letter-spacing: 0.5px;
  white-space: nowrap;
}

.brand-tagline {
  font-size: 13px;
  color: #999999;
  white-space: nowrap;
}

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

.site-nav .nav-list li a {
  display: block;
  padding: 8px 14px;
  font-size: 15px;
  font-weight: 500;
  color: #333333;
  border-radius: 4px;
  position: relative;
  transition: color 0.2s ease, background-color 0.2s ease;
}

.site-nav .nav-list li a:hover {
  color: #FF8C42;
  background-color: #fff5ee;
}

.site-nav .nav-list li a.is-current {
  color: #4A90E2;
  font-weight: 700;
}

.site-nav .nav-list li a.is-current::after {
  content: "";
  position: absolute;
  left: 14px;
  right: 14px;
  bottom: 2px;
  height: 2px;
  background-color: #4A90E2;
  border-radius: 1px;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
}

.nav-toggle-icon {
  display: block;
  width: 20px;
  height: 2px;
  background-color: #333333;
  position: relative;
  transition: background-color 0.2s ease;
}

.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: "";
  position: absolute;
  left: 0;
  width: 20px;
  height: 2px;
  background-color: #333333;
  transition: transform 0.2s ease;
}

.nav-toggle-icon::before {
  top: -6px;
}

.nav-toggle-icon::after {
  top: 6px;
}

.site-main {
  flex: 1;
}

.inner-main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 24px 20px 60px;
  width: 100%;
}

.site-footer {
  background-color: #2c3e50;
  color: #b8c4ce;
  margin-top: auto;
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 48px 20px 24px;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr 1fr;
  gap: 32px;
}

.footer-brand-name {
  font-size: 20px;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 8px;
}

.footer-tagline {
  font-size: 14px;
  line-height: 1.6;
  color: #8fa3b3;
}

.footer-heading {
  font-size: 15px;
  font-weight: 600;
  color: #ffffff;
  margin-bottom: 14px;
}

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

.footer-links li a {
  font-size: 14px;
  color: #b8c4ce;
  transition: color 0.2s ease;
}

.footer-links li a:hover {
  color: #FF8C42;
}

.footer-bottom {
  max-width: 1200px;
  margin: 0 auto;
  padding: 16px 20px 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.footer-bottom p {
  font-size: 13px;
  color: #7a8fa0;
}

/* 面包屑 */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  margin-bottom: 20px;
  padding: 12px 16px;
  background-color: #ffffff;
  border-radius: 6px;
  border: 1px solid #e8ecf0;
}

.breadcrumb a {
  color: #4A90E2;
}

.breadcrumb a:hover {
  color: #FF8C42;
}

.breadcrumb-sep {
  color: #cccccc;
  font-size: 12px;
}

.breadcrumb-current {
  color: #666666;
  font-weight: 500;
}

/* 页面标题区 */
.page-header {
  background-color: #ffffff;
  border-radius: 8px;
  padding: 32px 36px;
  margin-bottom: 28px;
  border: 1px solid #e8ecf0;
  border-left: 4px solid #FF8C42;
}

.page-title {
  font-size: 28px;
  font-weight: 700;
  color: #333333;
  margin-bottom: 10px;
  line-height: 1.3;
}

.page-description {
  font-size: 16px;
  line-height: 1.7;
  color: #666666;
  max-width: 800px;
}

/* ==========================================================================
   components — 通用组件
   ========================================================================== */

/* 按钮 */
.btn {
  display: inline-block;
  padding: 10px 22px;
  font-size: 15px;
  font-weight: 600;
  border-radius: 6px;
  border: none;
  cursor: pointer;
  transition: background-color 0.2s ease, transform 0.15s ease, box-shadow 0.2s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background-color: #FF8C42;
  color: #ffffff;
}

.btn-primary:hover {
  background-color: #f07a2a;
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(255, 140, 66, 0.3);
}

.btn-secondary {
  background-color: #4A90E2;
  color: #ffffff;
}

.btn-secondary:hover {
  background-color: #3a7fcf;
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(74, 144, 226, 0.3);
}

/* 区块标题 */
.section-title {
  font-size: 22px;
  font-weight: 700;
  color: #333333;
  margin-bottom: 8px;
  position: relative;
  padding-left: 14px;
}

.section-title::before {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  bottom: 4px;
  width: 4px;
  background-color: #FF8C42;
  border-radius: 2px;
}

.section-intro {
  font-size: 15px;
  color: #666666;
  margin-bottom: 20px;
  max-width: 700px;
}

/* 文字链接 */
.text-link {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  color: #4A90E2;
  margin-top: 10px;
  transition: color 0.2s ease;
}

.text-link:hover {
  color: #FF8C42;
}

/* 相关阅读列表 */
.related-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.related-list li a {
  display: block;
  padding: 12px 16px;
  background-color: #ffffff;
  border: 1px solid #e8ecf0;
  border-radius: 6px;
  font-size: 15px;
  color: #333333;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.related-list li a:hover {
  border-color: #FF8C42;
  box-shadow: 0 2px 8px rgba(255, 140, 66, 0.12);
  color: #333333;
}

/* 编辑推荐条目 */
.pick-item {
  background-color: #ffffff;
  border: 1px solid #e8ecf0;
  border-radius: 6px;
  padding: 16px 20px;
  transition: box-shadow 0.2s ease, transform 0.15s ease;
}

.pick-item:hover {
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
  transform: translateY(-2px);
}

.pick-title {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 6px;
}

.pick-title a {
  color: #333333;
}

.pick-title a:hover {
  color: #FF8C42;
}

.pick-reason {
  font-size: 14px;
  color: #666666;
  line-height: 1.6;
}

/* ==========================================================================
   pages — index 首页
   ========================================================================== */

.home-main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 24px 20px 60px;
}

/* Hero 首屏 */
.hero-section {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 40px;
  align-items: center;
  background-color: #ffffff;
  border-radius: 8px;
  padding: 40px 44px;
  margin-bottom: 36px;
  border: 1px solid #e8ecf0;
}

.hero-title {
  font-size: 32px;
  font-weight: 700;
  line-height: 1.3;
  color: #333333;
  margin-bottom: 16px;
}

.hero-title span {
  color: #FF8C42;
}

.hero-lead {
  font-size: 16px;
  line-height: 1.8;
  color: #666666;
  margin-bottom: 24px;
  max-width: 520px;
}

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

.hero-media {
  position: relative;
}

.hero-image {
  width: 100%;
  height: 280px;
  object-fit: cover;
  border-radius: 8px;
}

/* 焦点报道 */
.focus-report-section {
  margin-bottom: 40px;
}

.focus-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-top: 16px;
}

.focus-card {
  background-color: #ffffff;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid #e8ecf0;
  transition: box-shadow 0.2s ease, transform 0.15s ease;
}

.focus-card:hover {
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.08);
  transform: translateY(-2px);
}

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

.focus-card h3.focus-title {
  font-size: 18px;
  font-weight: 600;
  padding: 16px 20px 6px;
  line-height: 1.4;
}

.focus-excerpt {
  font-size: 14px;
  color: #666666;
  padding: 0 20px;
  line-height: 1.6;
}

.focus-card .text-link {
  margin: 8px 20px 18px;
}

/* 频道导航带 */
.channel-nav-section {
  margin-bottom: 40px;
}

.channel-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 16px;
}

.channel-tag {
  display: inline-block;
  padding: 10px 22px;
  background-color: #ffffff;
  border: 1px solid #e8ecf0;
  border-radius: 20px;
  font-size: 14px;
  font-weight: 500;
  color: #333333;
  transition: all 0.2s ease;
}

.channel-tag:hover {
  background-color: #FF8C42;
  border-color: #FF8C42;
  color: #ffffff;
  transform: translateY(-1px);
}

/* 最新资讯列表 */
.latest-list-section {
  margin-bottom: 40px;
}

.latest-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 16px;
}

.news-item {
  background-color: #ffffff;
  border: 1px solid #e8ecf0;
  border-radius: 6px;
  padding: 18px 22px;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.news-item:hover {
  border-color: #FF8C42;
  box-shadow: 0 2px 12px rgba(255, 140, 66, 0.1);
}

.news-title {
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 6px;
}

.news-title a {
  color: #333333;
}

.news-title a:hover {
  color: #FF8C42;
}

.news-summary {
  font-size: 14px;
  color: #666666;
  line-height: 1.6;
  margin-bottom: 8px;
}

.news-date {
  font-size: 13px;
  color: #999999;
}

/* 专题策划入口 */
.topic-cards-section {
  margin-bottom: 40px;
}

.topic-card-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-top: 16px;
}

.topic-card {
  display: block;
  background-color: #ffffff;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid #e8ecf0;
  transition: box-shadow 0.2s ease, transform 0.15s ease;
}

.topic-card:hover {
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.08);
  transform: translateY(-2px);
}

.topic-card img {
  width: 100%;
  height: 180px;
  object-fit: cover;
}

.topic-card-title {
  font-size: 18px;
  font-weight: 600;
  color: #333333;
  padding: 16px 20px 6px;
}

.topic-card-desc {
  font-size: 14px;
  color: #666666;
  padding: 0 20px 18px;
  line-height: 1.6;
}

/* 编辑推荐 */
.editor-picks-section {
  margin-bottom: 40px;
}

.editor-pick-list {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 20px;
  margin-top: 16px;
}

/* 信息来源与反馈 */
.source-feedback-section {
  background-color: #ffffff;
  border-radius: 8px;
  padding: 28px 32px;
  border: 1px solid #e8ecf0;
  margin-bottom: 20px;
}

.source-info p {
  font-size: 14px;
  color: #666666;
  line-height: 1.8;
  margin-top: 8px;
}

.source-info p:first-of-type {
  margin-top: 12px;
}

/* ==========================================================================
   pages — pindao 频道分类
   ========================================================================== */

.channel-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 24px;
  margin-bottom: 40px;
}

.channel-card {
  background-color: #ffffff;
  border-radius: 8px;
  padding: 28px 24px;
  border: 1px solid #e8ecf0;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  transition: box-shadow 0.2s ease, transform 0.15s ease;
}

.channel-card:hover {
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.08);
  transform: translateY(-2px);
}

.channel-icon {
  width: 64px;
  height: 64px;
  object-fit: cover;
  border-radius: 50%;
  margin-bottom: 16px;
}

.channel-name {
  font-size: 18px;
  font-weight: 600;
  color: #333333;
  margin-bottom: 10px;
}

.channel-desc {
  font-size: 14px;
  color: #666666;
  line-height: 1.6;
  margin-bottom: 16px;
  flex: 1;
}

.channel-link {
  font-size: 14px;
  font-weight: 600;
  color: #4A90E2;
}

.channel-link:hover {
  color: #FF8C42;
}

.channel-notes {
  background-color: #ffffff;
  border-radius: 8px;
  padding: 24px 28px;
  border: 1px solid #e8ecf0;
  margin-bottom: 32px;
}

.channel-notes h2 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 12px;
}

.channel-notes p {
  font-size: 14px;
  color: #666666;
  line-height: 1.7;
  margin-bottom: 8px;
}

.channel-related {
  background-color: #ffffff;
  border-radius: 8px;
  padding: 24px 28px;
  border: 1px solid #e8ecf0;
}

.channel-related h2 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 16px;
}

/* ==========================================================================
   pages — zhuanti 内容专题
   ========================================================================== */

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

.topic-item {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 24px;
  background-color: #ffffff;
  border-radius: 8px;
  padding: 20px;
  border: 1px solid #e8ecf0;
  margin-bottom: 16px;
  transition: box-shadow 0.2s ease;
}

.topic-item:hover {
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
}

.topic-media img {
  width: 100%;
  height: 180px;
  object-fit: cover;
  border-radius: 6px;
}

.topic-content {
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.topic-title {
  font-size: 19px;
  font-weight: 600;
  margin-bottom: 8px;
}

.topic-title a {
  color: #333333;
}

.topic-title a:hover {
  color: #FF8C42;
}

.topic-summary {
  font-size: 14px;
  color: #666666;
  line-height: 1.6;
  margin-bottom: 10px;
}

.topic-meta {
  font-size: 13px;
  color: #999999;
}

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

.overview-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 20px;
  margin-top: 16px;
}

.overview-card {
  background-color: #ffffff;
  border-radius: 8px;
  padding: 24px;
  border: 1px solid #e8ecf0;
}

.overview-title {
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 10px;
  color: #4A90E2;
}

.overview-card p {
  font-size: 14px;
  color: #666666;
  line-height: 1.7;
}

.overview-note {
  font-size: 14px;
  color: #666666;
  margin-top: 20px;
  line-height: 1.7;
}

.overview-note a {
  font-weight: 600;
}

.related-reading {
  background-color: #ffffff;
  border-radius: 8px;
  padding: 24px 28px;
  border: 1px solid #e8ecf0;
}

/* ==========================================================================
   pages — redian-jiedu 热点解读
   ========================================================================== */

.article-list-section {
  margin-bottom: 40px;
}

.article-item {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 24px;
  background-color: #ffffff;
  border-radius: 8px;
  padding: 20px;
  border: 1px solid #e8ecf0;
  margin-bottom: 16px;
  transition: box-shadow 0.2s ease;
}

.article-item:hover {
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
}

.article-media img {
  width: 100%;
  height: 180px;
  object-fit: cover;
  border-radius: 6px;
}

.article-body h3 {
  font-size: 19px;
  font-weight: 600;
  margin-bottom: 6px;
}

.article-body h3 a {
  color: #333333;
}

.article-body h3 a:hover {
  color: #FF8C42;
}

.article-date {
  font-size: 13px;
  color: #999999;
  margin-bottom: 10px;
}

.article-body p {
  font-size: 14px;
  color: #666666;
  line-height: 1.6;
  margin-bottom: 8px;
}

.read-more {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  color: #4A90E2;
  margin-top: 6px;
}

.read-more:hover {
  color: #FF8C42;
}

.method-note-section {
  background-color: #ffffff;
  border-radius: 8px;
  padding: 28px 32px;
  border: 1px solid #e8ecf0;
  margin-top: 40px;
}

.method-note-section > p {
  font-size: 14px;
  color: #666666;
  line-height: 1.7;
  margin-bottom: 12px;
}

.principle-list {
  list-style: disc;
  padding-left: 20px;
  margin-bottom: 12px;
}

.principle-list li {
  font-size: 14px;
  color: #666666;
  line-height: 1.7;
  margin-bottom: 6px;
}

.method-note-section a {
  font-weight: 600;
}

/* ==========================================================================
   pages — changwei-1 长尾专题一
   ========================================================================== */

.method-steps {
  margin-bottom: 40px;
}

.steps-wrap {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-top: 16px;
}

.step-item {
  display: grid;
  grid-template-columns: 52px 1fr;
  gap: 20px;
  background-color: #ffffff;
  border-radius: 8px;
  padding: 24px;
  border: 1px solid #e8ecf0;
  transition: box-shadow 0.2s ease;
}

.step-item:hover {
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
}

.step-num {
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background-color: #FF8C42;
  color: #ffffff;
  font-size: 20px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

.step-content h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 8px;
}

.step-content p {
  font-size: 14px;
  color: #666666;
  line-height: 1.7;
}

.step-content a {
  font-weight: 600;
  font-size: 14px;
}

.site-feature-map {
  background-color: #ffffff;
  border-radius: 8px;
  padding: 28px 32px;
  border: 1px solid #e8ecf0;
}

.feature-map-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  margin-top: 16px;
}

.feature-figure img {
  width: 100%;
  height: 240px;
  object-fit: cover;
  border-radius: 6px;
}

.feature-figure figcaption {
  font-size: 13px;
  color: #999999;
  margin-top: 8px;
  text-align: center;
}

.feature-map-list p {
  font-size: 14px;
  color: #666666;
  line-height: 1.7;
  margin-bottom: 12px;
}

.feature-map-list ul {
  margin-bottom: 14px;
}

.feature-map-list ul li {
  font-size: 14px;
  color: #666666;
  line-height: 1.7;
  padding-left: 18px;
  position: relative;
  margin-bottom: 6px;
}

.feature-map-list ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 8px;
  height: 8px;
  background-color: #7ED321;
  border-radius: 50%;
}

.feature-map-list ul li strong {
  color: #333333;
  font-weight: 600;
}

.feature-map-list a {
  font-weight: 600;
  font-size: 14px;
  margin-right: 16px;
}

/* ==========================================================================
   pages — changwei-2 长尾专题二
   ========================================================================== */

.angle-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 40px;
}

.angle-item {
  background-color: #ffffff;
  border-radius: 8px;
  padding: 24px;
  border: 1px solid #e8ecf0;
  transition: box-shadow 0.2s ease, transform 0.15s ease;
}

.angle-item:hover {
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
  transform: translateY(-2px);
}

.angle-title {
  font-size: 18px;
  font-weight: 600;
  color: #4A90E2;
  margin-bottom: 10px;
  padding-left: 14px;
  position: relative;
}

.angle-title::before {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  bottom: 4px;
  width: 4px;
  background-color: #7ED321;
  border-radius: 2px;
}

.angle-description {
  font-size: 14px;
  color: #666666;
  line-height: 1.7;
  margin-bottom: 10px;
}

.angle-example {
  font-size: 13px;
  color: #999999;
  line-height: 1.6;
  background-color: #F5F7FA;
  border-radius: 4px;
  padding: 10px 14px;
}

.example-note {
  background-color: #ffffff;
  border-radius: 8px;
  padding: 28px 32px;
  border: 1px solid #e8ecf0;
  margin-bottom: 40px;
}

.example-note .section-heading {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 16px;
  padding-left: 14px;
  position: relative;
}

.example-note .section-heading::before {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  bottom: 4px;
  width: 4px;
  background-color: #FF8C42;
  border-radius: 2px;
}

.example-note {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}

.example-note .section-heading {
  grid-column: 1 / -1;
}

.example-figure img {
  width: 100%;
  height: 220px;
  object-fit: cover;
  border-radius: 6px;
}

.example-figure figcaption {
  font-size: 13px;
  color: #999999;
  margin-top: 8px;
  text-align: center;
}

.example-text p {
  font-size: 14px;
  color: #666666;
  line-height: 1.7;
  margin-bottom: 12px;
}

.related-list .section-heading {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 16px;
  padding-left: 14px;
  position: relative;
}

.related-list .section-heading::before {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  bottom: 4px;
  width: 4px;
  background-color: #FF8C42;
  border-radius: 2px;
}

.related-items {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.related-item a {
  display: block;
  padding: 14px 18px;
  background-color: #ffffff;
  border: 1px solid #e8ecf0;
  border-radius: 6px;
  font-size: 15px;
  color: #333333;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.related-item a:hover {
  border-color: #FF8C42;
  box-shadow: 0 2px 8px rgba(255, 140, 66, 0.12);
  color: #333333;
}

/* ==========================================================================
   pages — 404
   ========================================================================== */

.error-main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 60px 20px;
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}

.error-section {
  background-color: #ffffff;
  border-radius: 8px;
  padding: 56px 48px;
  border: 1px solid #e8ecf0;
  text-align: center;
  max-width: 640px;
  width: 100%;
}

.error-code {
  font-size: 72px;
  font-weight: 700;
  color: #FF8C42;
  line-height: 1;
  margin-bottom: 16px;
}

.error-section h1 {
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 12px;
}

.error-desc {
  font-size: 15px;
  color: #666666;
  line-height: 1.7;
  margin-bottom: 28px;
}

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

.error-btn {
  display: inline-block;
  padding: 10px 24px;
  background-color: #FF8C42;
  color: #ffffff;
  font-size: 15px;
  font-weight: 600;
  border-radius: 6px;
  transition: background-color 0.2s ease, transform 0.15s ease;
}

.error-btn:hover {
  background-color: #f07a2a;
  color: #ffffff;
  transform: translateY(-1px);
}

.error-link {
  display: inline-block;
  padding: 10px 24px;
  background-color: #F5F7FA;
  color: #4A90E2;
  font-size: 15px;
  font-weight: 500;
  border-radius: 6px;
  border: 1px solid #e8ecf0;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.error-link:hover {
  border-color: #4A90E2;
  color: #FF8C42;
}

/* ==========================================================================
   responsive — 响应式适配
   ========================================================================== */

@media (max-width: 1024px) {
  .footer-inner {
    grid-template-columns: 1fr 1fr 1fr 1fr;
  }

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

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

@media (max-width: 768px) {
  .header-inner {
    height: 56px;
    padding: 0 16px;
  }

  .brand-tagline {
    display: none;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: absolute;
    top: 56px;
    left: 0;
    right: 0;
    background-color: #ffffff;
    border-bottom: 1px solid #e8ecf0;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    display: block;
  }

  .site-nav .nav-list {
    display: none;
    flex-direction: column;
    align-items: stretch;
    padding: 8px 0;
    max-height: calc(100vh - 56px);
    overflow-y: auto;
  }

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

  .site-nav .nav-list li a {
    padding: 14px 24px;
    border-radius: 0;
    font-size: 16px;
    border-bottom: 1px solid #f0f2f5;
  }

  .site-nav .nav-list li a.is-current::after {
    display: none;
  }

  .site-nav .nav-list li a.is-current {
    background-color: #fff5ee;
  }

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

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

  .hero-section {
    grid-template-columns: 1fr;
    padding: 28px 24px;
    gap: 24px;
  }

  .hero-title {
    font-size: 26px;
  }

  .hero-image {
    height: 200px;
  }

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

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

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

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

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

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

  .topic-media img {
    height: 200px;
  }

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

  .article-media img {
    height: 200px;
  }

  .feature-map-layout {
    grid-template-columns: 1fr;
  }

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

  .example-note {
    grid-template-columns: 1fr;
  }

  .example-note .section-heading {
    grid-column: 1;
  }

  .step-item {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .step-num {
    width: 44px;
    height: 44px;
    font-size: 18px;
  }

  .footer-inner {
    grid-template-columns: 1fr 1fr;
    gap: 24px;
    padding: 32px 16px 20px;
  }

  .footer-brand {
    grid-column: 1 / -1;
  }

  .page-header {
    padding: 24px 20px;
  }

  .page-title {
    font-size: 24px;
  }

  .breadcrumb {
    padding: 10px 14px;
    font-size: 13px;
    overflow-x: auto;
    white-space: nowrap;
  }

  .error-section {
    padding: 40px 24px;
  }

  .error-code {
    font-size: 56px;
  }

  .source-feedback-section {
    padding: 20px;
  }

  .topic-overview,
  .related-reading,
  .channel-notes,
  .channel-related,
  .method-note-section,
  .site-feature-map,
  .example-note {
    padding: 20px;
  }
}

@media (max-width: 480px) {
  .footer-inner {
    grid-template-columns: 1fr 1fr;
    gap: 20px;
  }

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

  .hero-actions .btn {
    width: 100%;
    text-align: center;
  }

  .news-item {
    padding: 14px 16px;
  }

  .focus-card img {
    height: 180px;
  }

  .topic-card img {
    height: 160px;
  }

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

  .error-actions a {
    width: 100%;
    text-align: center;
  }

  .footer-bottom {
    padding: 12px 16px 20px;
  }
}

/* 滚动出现动画（轻量增强，不影响初始可见性） */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.focus-card,
.topic-card,
.news-item,
.pick-item,
.channel-card,
.topic-item,
.article-item,
.step-item,
.angle-item {
  animation: fadeInUp 0.4s ease-out both;
}

.focus-card:nth-child(2),
.topic-card:nth-child(2),
.news-item:nth-child(2),
.pick-item:nth-child(2),
.channel-card:nth-child(2),
.topic-item:nth-child(2),
.article-item:nth-child(2),
.step-item:nth-child(2),
.angle-item:nth-child(2) {
  animation-delay: 0.08s;
}

.news-item:nth-child(3),
.pick-item:nth-child(3),
.channel-card:nth-child(3),
.topic-item:nth-child(3),
.article-item:nth-child(3),
.step-item:nth-child(3),
.angle-item:nth-child(3) {
  animation-delay: 0.16s;
}

.news-item:nth-child(4),
.channel-card:nth-child(4),
.topic-item:nth-child(4),
.article-item:nth-child(4),
.step-item:nth-child(4),
.angle-item:nth-child(4) {
  animation-delay: 0.24s;
}

.news-item:nth-child(5),
.channel-card:nth-child(5),
.topic-item:nth-child(5),
.article-item:nth-child(5),
.step-item:nth-child(5) {
  animation-delay: 0.32s;
}

.channel-card:nth-child(6),
.topic-item:nth-child(6),
.article-item:nth-child(6),
.step-item:nth-child(6) {
  animation-delay: 0.4s;
}