/* ==========================================================================
   糖豆视频 - 整站样式表
   视觉方向：教育指南风 · 深青绿 + 暖琥珀 · 浅米白背景
   ========================================================================== */

/* ==========================================================================
   Base
   ========================================================================== */

:root {
  --color-primary: #1E4D4A;
  --color-primary-dark: #163B38;
  --color-primary-light: #2A605C;
  --color-bg: #F5F0E6;
  --color-accent: #D98E32;
  --color-accent-dark: #B8741F;
  --color-text: #2B2B2B;
  --color-text-light: #6B6B6B;
  --color-white: #FFFFFF;
  --color-border: #E0D8C8;
  --color-border-light: #EBE5D8;
  --color-tag-bg: #F0EAE0;

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

  --container-width: 1200px;
  --sidebar-width: 260px;
  --radius: 6px;
  --radius-lg: 8px;

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

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

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

body {
  font-family: var(--font-family);
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100vh;
}

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

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

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

ul,
ol {
  list-style: none;
}

h1,
h2,
h3,
h4 {
  line-height: 1.4;
  font-weight: 700;
  color: var(--color-text);
}

p {
  margin-bottom: 0.5em;
}

/* ==========================================================================
   Layout - 全站骨架
   ========================================================================== */

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

.site-header {
  background-color: var(--color-primary);
  border-bottom: 3px solid var(--color-accent);
  position: sticky;
  top: 0;
  z-index: 100;
}

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

.brand-link {
  display: inline-flex;
  align-items: center;
  flex-shrink: 0;
  color: var(--color-white);
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 0.5px;
}

.brand-link:hover {
  color: var(--color-white);
  opacity: 0.9;
}

.brand-name {
  line-height: 1.2;
}

.site-nav {
  display: flex;
  align-items: center;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 6px;
  list-style: none;
}

.nav-list li {
  margin: 0;
}

.nav-list a {
  display: block;
  padding: 8px 14px;
  color: rgba(255, 255, 255, 0.85);
  font-size: 15px;
  font-weight: 500;
  border-radius: var(--radius);
  line-height: 1.4;
}

.nav-list a:hover {
  color: var(--color-white);
  background-color: rgba(255, 255, 255, 0.12);
}

.nav-list a.is-current {
  color: var(--color-white);
  background-color: rgba(255, 255, 255, 0.16);
  font-weight: 700;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 44px;
  height: 44px;
  padding: 10px;
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.4);
  border-radius: var(--radius);
  cursor: pointer;
  gap: 5px;
  flex-shrink: 0;
}

.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  background-color: var(--color-white);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

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

.site-footer {
  background-color: var(--color-primary-dark);
  color: rgba(255, 255, 255, 0.8);
  margin-top: 0;
}

.footer-inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 48px 24px 32px;
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: 40px;
}

.footer-col h3 {
  color: var(--color-white);
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 14px;
}

.footer-col p {
  color: rgba(255, 255, 255, 0.7);
  font-size: 14px;
  line-height: 1.7;
  margin-bottom: 14px;
}

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

.footer-links a {
  color: rgba(255, 255, 255, 0.75);
  font-size: 14px;
  line-height: 1.6;
}

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

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  padding: 16px 24px;
  text-align: center;
}

.footer-bottom p {
  max-width: var(--container-width);
  margin: 0 auto;
  color: rgba(255, 255, 255, 0.55);
  font-size: 13px;
}

/* ==========================================================================
   Layout - 内页通用
   ========================================================================== */

.inner-main {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 32px 24px 56px;
  width: 100%;
  flex: 1 0 auto;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--color-text-light);
  margin-bottom: 20px;
}

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

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

.breadcrumb-sep {
  color: var(--color-text-light);
}

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

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

.page-title {
  font-size: 30px;
  font-weight: 700;
  line-height: 1.35;
  color: var(--color-text);
  margin-bottom: 10px;
}

.page-description {
  font-size: 16px;
  color: var(--color-text-light);
  line-height: 1.7;
  max-width: 720px;
}

/* 侧栏布局：主内容在前，侧栏在后（DOM 顺序） */
.page-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
}

.sidebar-left {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
}

.sidebar-left .page-layout,
.page-layout.sidebar-left {
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr);
  align-items: start;
}

.sidebar-left .sidebar,
.page-layout.sidebar-left > .sidebar {
  order: 1;
  position: sticky;
  top: calc(var(--header-height) + 20px);
}

.sidebar-left .inner-main,
.page-layout.sidebar-left > .inner-main {
  order: 2;
}

/* FAQ 页的独立布局壳 */
.layout-shell {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 32px 24px 56px;
  width: 100%;
}

.layout-shell.sidebar-left {
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr);
  align-items: start;
}

.layout-shell.sidebar-left .sidebar {
  order: 1;
  position: sticky;
  top: calc(var(--header-height) + 20px);
}

.layout-shell.sidebar-left .main-content {
  order: 2;
  min-width: 0;
}

/* 侧栏通用 */
.sidebar {
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 24px;
}

.sidebar-inner {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.sidebar-title {
  font-size: 17px;
  font-weight: 700;
  color: var(--color-text);
  padding-bottom: 12px;
  border-bottom: 2px solid var(--color-primary);
  margin-bottom: 4px;
}

.sidebar-nav {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.sidebar-nav li {
  margin: 0;
}

.sidebar-nav a {
  display: block;
  padding: 9px 12px;
  color: var(--color-text);
  font-size: 15px;
  border-left: 3px solid transparent;
  border-radius: 0 var(--radius) var(--radius) 0;
  line-height: 1.5;
}

.sidebar-nav a:hover {
  background-color: var(--color-bg);
  color: var(--color-primary);
  border-left-color: var(--color-accent);
}

.sidebar-note {
  background-color: var(--color-bg);
  border-radius: var(--radius);
  padding: 14px 16px;
  font-size: 14px;
  line-height: 1.65;
  color: var(--color-text-light);
}

.sidebar-note p {
  margin-bottom: 8px;
}

.sidebar-note p:last-child {
  margin-bottom: 0;
}

.sidebar-link {
  display: inline-block;
  font-weight: 600;
  font-size: 14px;
  color: var(--color-primary);
}

.sidebar-link:hover {
  color: var(--color-accent-dark);
}

/* ==========================================================================
   Components - 通用模块
   ========================================================================== */

.section-title {
  font-size: 22px;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.4;
  margin-bottom: 12px;
}

.section-desc {
  font-size: 15px;
  color: var(--color-text-light);
  line-height: 1.7;
  margin-bottom: 24px;
  max-width: 760px;
}

.link-more {
  display: inline-block;
  margin-top: 16px;
  font-size: 15px;
  font-weight: 600;
  color: var(--color-primary);
  padding: 6px 0;
  border-bottom: 2px solid var(--color-accent);
}

.link-more:hover {
  color: var(--color-accent-dark);
  border-bottom-color: var(--color-accent-dark);
}

/* 相关链接条 */
.related-links {
  margin-top: 40px;
  padding-top: 24px;
  border-top: 1px solid var(--color-border);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
}

.related-links-label {
  font-size: 14px;
  color: var(--color-text-light);
  margin-right: 4px;
}

.related-links-item {
  display: inline-block;
  padding: 6px 16px;
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  font-size: 14px;
  color: var(--color-primary);
  line-height: 1.5;
}

.related-links-item:hover {
  border-color: var(--color-primary);
  background-color: var(--color-bg);
}

/* 提示框 */
.tips-box {
  background-color: var(--color-bg);
  border-left: 4px solid var(--color-accent);
  border-radius: var(--radius);
  padding: 20px 24px;
}

.tips-lead {
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 12px;
}

.tips-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.tips-list li {
  position: relative;
  padding-left: 20px;
  font-size: 15px;
  line-height: 1.65;
}

.tips-list li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 10px;
  width: 8px;
  height: 8px;
  background-color: var(--color-accent);
  border-radius: 2px;
}

.tips-list strong {
  color: var(--color-text);
  font-weight: 600;
}

/* 相关卡片 */
.related-card {
  display: block;
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 24px;
  text-decoration: none;
  transition: box-shadow var(--transition), transform var(--transition);
}

.related-card:hover {
  box-shadow: 0 4px 16px rgba(30, 77, 74, 0.1);
  transform: translateY(-2px);
  color: var(--color-text);
}

.related-card h3 {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--color-primary);
}

.related-card:hover h3 {
  color: var(--color-accent-dark);
}

.related-card p {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.65;
  margin-bottom: 0;
}

.related-cards {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

/* ==========================================================================
   Components - 首页 Hero
   ========================================================================== */

.hero-section {
  background-color: var(--color-primary);
  padding: 48px 0;
}

.hero-section .hero-media,
.hero-section .hero-content {
  /* 内部使用 grid 布局 */
}

.hero-section {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  gap: 40px;
  align-items: center;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 48px 24px;
}

.hero-media {
  min-width: 0;
}

.hero-figure {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: var(--color-primary-dark);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
}

.hero-figure img {
  width: 100%;
  height: 340px;
  object-fit: cover;
  display: block;
}

.hero-content {
  min-width: 0;
}

.hero-title {
  font-size: 32px;
  font-weight: 700;
  line-height: 1.35;
  color: var(--color-white);
  margin-bottom: 16px;
}

.hero-desc {
  font-size: 16px;
  line-height: 1.75;
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: 24px;
  max-width: 480px;
}

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

.btn-primary {
  display: inline-block;
  padding: 10px 24px;
  background-color: var(--color-accent);
  color: var(--color-white);
  font-size: 15px;
  font-weight: 600;
  border-radius: var(--radius);
  border: 2px solid var(--color-accent);
  line-height: 1.5;
  cursor: pointer;
  transition: background-color var(--transition), border-color var(--transition);
}

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

.btn-secondary {
  display: inline-block;
  padding: 10px 24px;
  background-color: transparent;
  color: var(--color-white);
  font-size: 15px;
  font-weight: 600;
  border-radius: var(--radius);
  border: 2px solid rgba(255, 255, 255, 0.6);
  line-height: 1.5;
  cursor: pointer;
  transition: background-color var(--transition), border-color var(--transition);
}

.btn-secondary:hover {
  background-color: rgba(255, 255, 255, 0.12);
  border-color: var(--color-white);
  color: var(--color-white);
}

.btn-text {
  display: inline-block;
  padding: 10px 8px;
  background-color: transparent;
  color: rgba(255, 255, 255, 0.85);
  font-size: 15px;
  font-weight: 500;
  border-bottom: 2px solid transparent;
  line-height: 1.5;
  cursor: pointer;
  transition: color var(--transition), border-color var(--transition);
}

.btn-text:hover {
  color: var(--color-white);
  border-bottom-color: var(--color-accent);
}

/* ==========================================================================
   Components - 首页频道分类总览
   ========================================================================== */

.channel-section,
.topic-section,
.guide-section,
.update-section,
.boundary-section {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 48px 24px;
}

.section-head {
  margin-bottom: 28px;
}

.section-head .section-title {
  font-size: 24px;
  margin-bottom: 8px;
}

.section-head .section-desc {
  margin-bottom: 0;
}

.channel-layout {
  display: grid;
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr);
  gap: 32px;
  align-items: start;
}

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

.channel-sidebar .sidebar-title {
  font-size: 16px;
  margin-bottom: 12px;
}

.sidebar-list {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.sidebar-list a {
  display: block;
  padding: 8px 12px;
  color: var(--color-text);
  font-size: 15px;
  border-left: 3px solid transparent;
  line-height: 1.5;
}

.sidebar-list a:hover {
  background-color: var(--color-bg);
  color: var(--color-primary);
  border-left-color: var(--color-accent);
}

.channel-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.channel-item {
  display: grid;
  grid-template-columns: 140px minmax(0, 1fr);
  gap: 16px;
  padding: 18px 24px;
  border-bottom: 1px solid var(--color-border-light);
  align-items: baseline;
}

.channel-item:last-child {
  border-bottom: none;
}

.channel-name {
  font-size: 16px;
  font-weight: 600;
  color: var(--color-primary);
  margin: 0;
  line-height: 1.4;
}

.channel-desc {
  font-size: 15px;
  color: var(--color-text-light);
  line-height: 1.6;
  margin: 0;
}

/* ==========================================================================
   Components - 首页专题片单精选
   ========================================================================== */

.topic-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 24px;
}

.topic-card {
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: box-shadow var(--transition), transform var(--transition);
  display: flex;
  flex-direction: column;
}

.topic-card:hover {
  box-shadow: 0 6px 20px rgba(30, 77, 74, 0.12);
  transform: translateY(-3px);
}

.topic-media {
  overflow: hidden;
  background-color: var(--color-bg);
  aspect-ratio: 16 / 9;
}

.topic-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.topic-body {
  padding: 20px 24px 24px;
  flex: 1;
}

.topic-name {
  font-size: 17px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 8px;
  line-height: 1.4;
}

.topic-desc {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.65;
  margin: 0;
}

/* ==========================================================================
   Components - 首页观看指南步骤
   ========================================================================== */

.guide-steps {
  list-style: none;
  counter-reset: guide-step;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 20px;
  padding: 0;
  margin: 0;
}

.guide-step {
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 24px;
  position: relative;
  counter-increment: guide-step;
}

.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background-color: var(--color-primary);
  color: var(--color-white);
  font-size: 16px;
  font-weight: 700;
  border-radius: 50%;
  margin-bottom: 14px;
}

.step-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 8px;
  line-height: 1.4;
}

.step-desc {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.65;
  margin: 0;
}

/* ==========================================================================
   Components - 首页看点动态摘要
   ========================================================================== */

.update-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.update-item {
  display: grid;
  grid-template-columns: 100px minmax(0, 1fr);
  gap: 16px;
  padding: 18px 24px;
  border-bottom: 1px solid var(--color-border-light);
  align-items: baseline;
}

.update-item:last-child {
  border-bottom: none;
}

.update-date {
  font-size: 14px;
  color: var(--color-accent-dark);
  font-weight: 600;
  white-space: nowrap;
}

.update-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 4px;
  line-height: 1.4;
}

.update-desc {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.6;
  margin: 0;
}

/* ==========================================================================
   Components - 首页内容边界提示
   ========================================================================== */

.boundary-card {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.boundary-col {
  padding: 28px 32px;
}

.boundary-col + .boundary-col {
  border-left: 1px solid var(--color-border-light);
  background-color: var(--color-bg);
}

.boundary-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--color-primary);
  display: inline-block;
}

.boundary-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.boundary-list li {
  position: relative;
  padding-left: 18px;
  font-size: 15px;
  line-height: 1.65;
  color: var(--color-text);
}

.boundary-list li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 10px;
  width: 6px;
  height: 6px;
  background-color: var(--color-accent);
  border-radius: 50%;
}

/* ==========================================================================
   Pages - 频道分类页
   ========================================================================== */

.page-media {
  margin-bottom: 36px;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: var(--color-bg);
}

.page-media img {
  width: 100%;
  height: 240px;
  object-fit: cover;
}

.page-media figcaption {
  padding: 10px 16px;
  background-color: var(--color-white);
  border-top: 1px solid var(--color-border-light);
  font-size: 13px;
  color: var(--color-text-light);
  line-height: 1.5;
}

.channel-group {
  margin-bottom: 40px;
}

.channel-group .section-title {
  font-size: 20px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--color-primary);
  display: inline-block;
  margin-bottom: 20px;
}

.channel-group .channel-list {
  background: transparent;
  border: none;
  gap: 12px;
}

.channel-group .channel-item {
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius);
  padding: 20px 24px;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  display: block;
}

.channel-group .channel-card h3 {
  font-size: 16px;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 6px;
}

.channel-group .channel-card .channel-desc {
  font-size: 15px;
  color: var(--color-text);
  line-height: 1.65;
  margin-bottom: 6px;
}

.channel-group .channel-card .channel-scene {
  font-size: 13px;
  color: var(--color-text-light);
  line-height: 1.6;
  margin: 0;
  padding-top: 6px;
  border-top: 1px dashed var(--color-border);
}

.guide-cta {
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 28px 32px;
  margin-top: 40px;
}

.guide-cta .section-title {
  font-size: 19px;
  margin-bottom: 10px;
}

.guide-cta p {
  font-size: 15px;
  color: var(--color-text-light);
  margin-bottom: 16px;
}

.cta-link {
  display: inline-block;
  margin-right: 12px;
  padding: 8px 20px;
  background-color: var(--color-primary);
  color: var(--color-white);
  border-radius: var(--radius);
  font-size: 14px;
  font-weight: 600;
  border: 2px solid var(--color-primary);
}

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

/* ==========================================================================
   Pages - 专题片单页
   ========================================================================== */

.topics-intro {
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 28px 32px;
  margin-bottom: 32px;
}

.intro-lead {
  font-size: 16px;
  line-height: 1.75;
  color: var(--color-text);
  margin-bottom: 12px;
}

.intro-note {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.7;
  margin: 0;
}

.intro-note a {
  color: var(--color-primary);
  font-weight: 600;
}

.topic-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
  margin-bottom: 32px;
}

.topic-grid .section-title {
  grid-column: 1 / -1;
  font-size: 22px;
  margin-bottom: 4px;
}

.topic-card {
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: box-shadow var(--transition), transform var(--transition);
}

.topic-card:hover {
  box-shadow: 0 6px 20px rgba(30, 77, 74, 0.12);
  transform: translateY(-3px);
}

.topic-cover {
  overflow: hidden;
  background-color: var(--color-bg);
  aspect-ratio: 16 / 9;
}

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

.topic-card-body {
  padding: 20px 24px 24px;
  flex: 1;
}

.topic-name {
  font-size: 18px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 8px;
  line-height: 1.4;
}

.topic-angle {
  font-size: 14px;
  color: var(--color-text);
  line-height: 1.65;
  margin-bottom: 10px;
}

.topic-audience {
  font-size: 13px;
  color: var(--color-text-light);
  line-height: 1.6;
  margin: 0;
  padding-top: 10px;
  border-top: 1px dashed var(--color-border);
}

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

.channel-related {
  background-color: var(--color-bg);
  border-radius: var(--radius);
  padding: 16px 20px;
  margin-bottom: 24px;
}

.channel-related p {
  font-size: 14px;
  color: var(--color-text-light);
  margin: 0;
}

.channel-related a {
  color: var(--color-primary);
  font-weight: 600;
  margin-right: 8px;
}

/* ==========================================================================
   Pages - 看点动态页
   ========================================================================== */

.updates-intro {
  margin-bottom: 32px;
}

.updates-intro .section-title {
  font-size: 20px;
  margin-bottom: 12px;
}

.intro-content p {
  font-size: 15px;
  color: var(--color-text-light);
  line-height: 1.7;
  margin-bottom: 10px;
}

.timeline-section {
  margin-bottom: 40px;
}

.timeline-section .section-title {
  font-size: 20px;
  margin-bottom: 20px;
}

.timeline-list {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0;
  padding-left: 24px;
  border-left: 2px solid var(--color-border);
}

.timeline-item {
  position: relative;
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius);
  padding: 20px 24px;
  margin-bottom: 20px;
}

.timeline-item::before {
  content: "";
  position: absolute;
  left: -31px;
  top: 26px;
  width: 12px;
  height: 12px;
  background-color: var(--color-accent);
  border: 2px solid var(--color-white);
  border-radius: 50%;
  box-shadow: 0 0 0 2px var(--color-accent);
}

.timeline-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 8px;
  flex-wrap: wrap;
}

.timeline-date {
  font-size: 14px;
  color: var(--color-accent-dark);
  font-weight: 600;
}

.timeline-tag {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
  line-height: 1.6;
  background-color: var(--color-tag-bg);
  color: var(--color-primary);
}

.timeline-tag.tag-channel {
  background-color: rgba(30, 77, 74, 0.12);
  color: var(--color-primary);
}

.timeline-tag.tag-topic {
  background-color: rgba(217, 142, 50, 0.15);
  color: var(--color-accent-dark);
}

.timeline-tag.tag-guide {
  background-color: rgba(30, 77, 74, 0.08);
  color: var(--color-primary-dark);
}

.timeline-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 6px;
  line-height: 1.4;
}

.timeline-desc {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.65;
  margin-bottom: 8px;
}

.timeline-link {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  color: var(--color-primary);
}

.timeline-link:hover {
  color: var(--color-accent-dark);
}

.updates-media {
  margin: 32px 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: var(--color-bg);
}

.updates-media img {
  width: 100%;
  height: 260px;
  object-fit: cover;
}

.updates-media figcaption {
  padding: 10px 16px;
  background-color: var(--color-white);
  border-top: 1px solid var(--color-border-light);
  font-size: 13px;
  color: var(--color-text-light);
  line-height: 1.5;
}

/* ==========================================================================
   Pages - 观看指南页
   ========================================================================== */

.guide-intro {
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 28px 32px;
  margin-bottom: 32px;
}

.guide-intro .section-title {
  font-size: 20px;
  margin-bottom: 12px;
}

.guide-intro p {
  font-size: 15px;
  line-height: 1.75;
  color: var(--color-text);
  margin-bottom: 10px;
}

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

.guide-steps .section-title {
  font-size: 20px;
  margin-bottom: 20px;
}

.steps-list {
  display: flex;
  flex-direction: column;
  gap: 20px;
  counter-reset: step-counter;
}

.step-item {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 20px;
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 24px;
  align-items: start;
}

.step-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background-color: var(--color-primary);
  color: var(--color-white);
  font-size: 20px;
  font-weight: 700;
  border-radius: 8px;
  line-height: 1;
}

.step-content h3 {
  font-size: 17px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 8px;
  line-height: 1.4;
}

.step-content p {
  font-size: 15px;
  color: var(--color-text-light);
  line-height: 1.7;
  margin: 0;
}

.verify-tips {
  margin-bottom: 40px;
}

.verify-tips .section-title {
  font-size: 20px;
  margin-bottom: 16px;
}

.boundary-note {
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 28px 32px;
  margin-bottom: 40px;
}

.boundary-note .section-title {
  font-size: 20px;
  margin-bottom: 12px;
}

.boundary-note p {
  font-size: 15px;
  color: var(--color-text-light);
  line-height: 1.75;
  margin-bottom: 10px;
}

.guide-media {
  margin-top: 40px;
}

.guide-media .section-title {
  font-size: 20px;
  margin-bottom: 16px;
}

.guide-figure {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: var(--color-bg);
}

.guide-figure img {
  width: 100%;
  height: 280px;
  object-fit: cover;
}

.guide-figure figcaption {
  padding: 10px 16px;
  background-color: var(--color-white);
  border-top: 1px solid var(--color-border-light);
  font-size: 13px;
  color: var(--color-text-light);
  line-height: 1.5;
}

/* ==========================================================================
   Pages - 常见疑问页
   ========================================================================== */

.main-content {
  min-width: 0;
}

.faq-group {
  margin-bottom: 40px;
}

.faq-group .section-title {
  font-size: 20px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--color-primary);
  display: inline-block;
  margin-bottom: 20px;
}

.content-media {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: var(--color-bg);
  margin-bottom: 20px;
}

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

.content-media figcaption {
  padding: 8px 16px;
  background-color: var(--color-white);
  border-top: 1px solid var(--color-border-light);
  font-size: 13px;
  color: var(--color-text-light);
  line-height: 1.5;
}

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

.faq-item {
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius);
  overflow: hidden;
}

.faq-item summary {
  padding: 16px 20px;
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text);
  cursor: pointer;
  list-style: none;
  position: relative;
  padding-right: 40px;
  line-height: 1.5;
  transition: background-color var(--transition);
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "+";
  position: absolute;
  right: 16px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 20px;
  font-weight: 400;
  color: var(--color-primary);
  transition: transform var(--transition);
}

.faq-item[open] summary {
  background-color: var(--color-bg);
  color: var(--color-primary);
}

.faq-item[open] summary::after {
  content: "−";
}

.faq-item summary:hover {
  background-color: var(--color-bg);
}

.faq-answer {
  padding: 4px 20px 16px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--color-text-light);
  border-top: 1px dashed var(--color-border);
  padding-top: 14px;
}

.faq-answer p {
  margin-bottom: 8px;
}

.faq-answer p:last-child {
  margin-bottom: 0;
}

.faq-bottom-card {
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 28px 32px;
  margin-top: 40px;
}

.faq-bottom-card .section-title {
  font-size: 18px;
  margin-bottom: 8px;
}

.faq-bottom-card p {
  font-size: 15px;
  color: var(--color-text-light);
  margin: 0;
}

.faq-bottom-card a {
  color: var(--color-primary);
  font-weight: 600;
}

/* ==========================================================================
   Pages - 内容边界页
   ========================================================================== */

.boundary-intro {
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 28px 32px;
  margin-bottom: 32px;
}

.boundary-intro .section-title {
  font-size: 20px;
  margin-bottom: 12px;
}

.boundary-intro p {
  font-size: 15px;
  line-height: 1.75;
  color: var(--color-text);
  margin-bottom: 10px;
}

.scope-list,
.not-provided {
  margin-bottom: 40px;
}

.scope-list .section-title,
.not-provided .section-title {
  font-size: 20px;
  margin-bottom: 8px;
}

.scope-list .section-desc,
.not-provided .section-desc {
  margin-bottom: 20px;
}

.scope-items,
.not-provided-items {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.scope-item,
.not-provided-item {
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius);
  padding: 20px 24px;
}

.scope-item .item-title,
.not-provided-item .item-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 6px;
  line-height: 1.4;
}

.scope-item .item-desc,
.not-provided-item .item-desc {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.65;
  margin: 0;
}

.organization-note {
  margin-bottom: 40px;
}

.organization-note .section-title {
  font-size: 20px;
  margin-bottom: 20px;
}

.organization-content {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.2fr);
  gap: 24px;
  align-items: start;
}

.organization-figure {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: var(--color-bg);
}

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

.organization-figure figcaption {
  padding: 8px 16px;
  background-color: var(--color-white);
  border-top: 1px solid var(--color-border-light);
  font-size: 13px;
  color: var(--color-text-light);
  line-height: 1.5;
}

.organization-text p {
  font-size: 15px;
  line-height: 1.75;
  color: var(--color-text);
  margin-bottom: 12px;
}

.boundary-table-section {
  margin-bottom: 40px;
}

.boundary-table-section .section-title {
  font-size: 20px;
  margin-bottom: 8px;
}

.boundary-table-section .section-desc {
  margin-bottom: 20px;
}

.boundary-table {
  width: 100%;
  border-collapse: collapse;
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  font-size: 14px;
}

.boundary-table th,
.boundary-table td {
  padding: 14px 18px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--color-border-light);
  line-height: 1.6;
}

.boundary-table thead th {
  background-color: var(--color-primary);
  color: var(--color-white);
  font-weight: 600;
  font-size: 15px;
  border-bottom: none;
}

.boundary-table tbody th {
  background-color: var(--color-bg);
  font-weight: 600;
  color: var(--color-text);
  width: 18%;
}

.boundary-table tbody tr:last-child th,
.boundary-table tbody tr:last-child td {
  border-bottom: none;
}

.boundary-table td {
  color: var(--color-text-light);
}

/* ==========================================================================
   Pages - 关于本站页
   ========================================================================== */

.about-intro {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
  gap: 32px;
  align-items: center;
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 32px;
  margin-bottom: 40px;
}

.about-intro-content .section-title {
  font-size: 20px;
  margin-bottom: 12px;
}

.about-intro-content p {
  font-size: 15px;
  line-height: 1.75;
  color: var(--color-text);
  margin-bottom: 10px;
}

.about-intro-media {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: var(--color-bg);
}

.about-intro-media img {
  width: 100%;
  height: 220px;
  object-fit: cover;
}

.about-intro-media figcaption {
  padding: 8px 16px;
  background-color: var(--color-white);
  border-top: 1px solid var(--color-border-light);
  font-size: 13px;
  color: var(--color-text-light);
  line-height: 1.5;
}

.team-functions,
.section-system,
.feedback-path {
  margin-bottom: 40px;
}

.team-functions .section-title,
.section-system .section-title,
.feedback-path .section-title {
  font-size: 20px;
  margin-bottom: 8px;
}

.team-functions .section-desc,
.section-system .section-desc,
.feedback-path .section-desc {
  margin-bottom: 20px;
}

.function-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

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

.function-name {
  font-size: 17px;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 8px;
  line-height: 1.4;
}

.function-duty {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.65;
  margin-bottom: 14px;
}

.function-related {
  padding-top: 12px;
  border-top: 1px dashed var(--color-border);
}

.function-related a {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  color: var(--color-primary);
  margin-right: 12px;
}

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

.system-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.system-item {
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius);
  padding: 20px 24px;
}

.system-name {
  font-size: 16px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 6px;
  line-height: 1.4;
}

.system-desc {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.65;
  margin: 0;
}

.feedback-options {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

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

.feedback-name {
  font-size: 16px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 8px;
  line-height: 1.4;
}

.feedback-desc {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.65;
  margin-bottom: 14px;
}

.feedback-link {
  padding-top: 12px;
  border-top: 1px dashed var(--color-border);
}

.feedback-link a {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  color: var(--color-primary);
}

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

.feedback-note {
  margin-top: 20px;
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.7;
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius);
  padding: 16px 20px;
}

/* ==========================================================================
   Pages - 404
   ========================================================================== */

.error-main {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 80px 24px;
  flex: 1 0 auto;
}

.error-section {
  text-align: center;
  max-width: 560px;
  width: 100%;
  background-color: var(--color-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 48px 40px;
}

.error-code {
  font-size: 64px;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1.1;
  margin-bottom: 12px;
}

.error-section h1 {
  font-size: 24px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 12px;
}

.error-desc {
  font-size: 15px;
  color: var(--color-text-light);
  line-height: 1.7;
  margin-bottom: 24px;
}

.error-back {
  display: inline-block;
  padding: 10px 28px;
  background-color: var(--color-primary);
  color: var(--color-white);
  font-size: 15px;
  font-weight: 600;
  border-radius: var(--radius);
  border: 2px solid var(--color-primary);
  margin-bottom: 24px;
}

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

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

.error-links a {
  display: inline-block;
  padding: 8px 16px;
  background-color: var(--color-bg);
  color: var(--color-primary);
  font-size: 14px;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
}

.error-links a:hover {
  border-color: var(--color-primary);
  background-color: var(--color-white);
}

/* ==========================================================================
   Responsive - 桌面（1200px 以下）
   ========================================================================== */

@media (max-width: 1100px) {
  .footer-inner {
    grid-template-columns: 1.2fr 1fr 1fr;
    gap: 32px;
  }

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

  .hero-section {
    gap: 32px;
  }

  .hero-title {
    font-size: 28px;
  }

  .topic-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

/* ==========================================================================
   Responsive - 平板（900px 以下）
   ========================================================================== */

@media (max-width: 900px) {
  .page-layout.sidebar-left,
  .sidebar-left .page-layout,
  .layout-shell.sidebar-left {
    grid-template-columns: minmax(0, 1fr);
  }

  .sidebar-left .sidebar,
  .page-layout.sidebar-left > .sidebar,
  .layout-shell.sidebar-left .sidebar {
    position: static;
    order: 2;
  }

  .sidebar-left .inner-main,
  .page-layout.sidebar-left > .inner-main,
  .layout-shell.sidebar-left .main-content {
    order: 1;
  }

  .hero-section {
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
  }

  .hero-figure img {
    height: 280px;
  }

  .channel-layout {
    grid-template-columns: minmax(0, 1fr);
    gap: 20px;
  }

  .channel-sidebar {
    order: 2;
  }

  .channel-list {
    order: 1;
  }

  .guide-steps {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }

  .function-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .organization-content {
    grid-template-columns: minmax(0, 1fr);
  }

  .about-intro {
    grid-template-columns: minmax(0, 1fr);
  }
}

/* ==========================================================================
   Responsive - 手机（768px 以下）
   ========================================================================== */

@media (max-width: 768px) {
  .header-inner {
    height: auto;
    min-height: var(--header-height);
    padding: 10px 16px;
    flex-wrap: wrap;
    gap: 8px;
  }

  .nav-toggle {
    display: flex;
    margin-left: auto;
  }

  .site-nav {
    order: 3;
    flex-basis: 100%;
    display: block;
  }

  .nav-list {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    padding: 8px 0 4px;
    width: 100%;
  }

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

  .nav-list a {
    padding: 12px 12px;
    font-size: 15px;
    border-radius: var(--radius);
  }

  .brand-name {
    font-size: 20px;
  }

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

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

  .page-description {
    font-size: 15px;
  }

  .breadcrumb {
    font-size: 13px;
    margin-bottom: 16px;
    flex-wrap: wrap;
  }

  .page-header {
    margin-bottom: 24px;
    padding-bottom: 18px;
  }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: 28px;
    padding: 36px 20px 24px;
  }

  .footer-about {
    grid-column: auto;
  }

  .footer-bottom {
    padding: 14px 16px;
    font-size: 12px;
  }

  .hero-section {
    padding: 32px 16px;
    gap: 20px;
  }

  .hero-figure img {
    height: 220px;
  }

  .hero-title {
    font-size: 24px;
    line-height: 1.4;
  }

  .hero-desc {
    font-size: 15px;
    margin-bottom: 20px;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
    gap: 10px;
  }

  .btn-primary,
  .btn-secondary,
  .btn-text {
    text-align: center;
    padding: 12px 16px;
  }

  .channel-section,
  .topic-section,
  .guide-section,
  .update-section,
  .boundary-section {
    padding: 36px 16px;
  }

  .section-head .section-title {
    font-size: 21px;
  }

  .section-head .section-desc {
    font-size: 14px;
  }

  .channel-item {
    grid-template-columns: 1fr;
    gap: 6px;
    padding: 16px 20px;
  }

  .channel-name {
    font-size: 16px;
  }

  .channel-desc {
    font-size: 14px;
  }

  .topic-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 16px;
  }

  .topic-body {
    padding: 16px 18px 20px;
  }

  .topic-name {
    font-size: 16px;
  }

  .guide-steps {
    grid-template-columns: minmax(0, 1fr);
    gap: 14px;
  }

  .guide-step {
    padding: 20px;
  }

  .step-num {
    width: 32px;
    height: 32px;
    font-size: 15px;
    margin-bottom: 10px;
  }

  .update-item {
    grid-template-columns: 1fr;
    gap: 6px;
    padding: 16px 20px;
  }

  .update-date {
    font-size: 13px;
  }

  .update-title {
    font-size: 15px;
  }

  .boundary-card {
    grid-template-columns: minmax(0, 1fr);
  }

  .boundary-col {
    padding: 20px;
  }

  .boundary-col + .boundary-col {
    border-left: none;
    border-top: 1px solid var(--color-border-light);
  }

  .boundary-title {
    font-size: 17px;
  }

  .boundary-list li {
    font-size: 14px;
  }

  .related-cards,
  .related-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 14px;
  }

  .related-card {
    padding: 18px 20px;
  }

  .related-links {
    gap: 8px;
    margin-top: 28px;
  }

  .related-links-item {
    padding: 6px 12px;
    font-size: 13px;
  }

  .page-media img {
    height: 180px;
  }

  .channel-group .channel-item {
    padding: 16px 18px;
  }

  .guide-cta {
    padding: 20px;
  }

  .cta-link {
    display: block;
    margin: 0 0 10px 0;
    text-align: center;
  }

  .topics-intro,
  .guide-intro,
  .boundary-intro {
    padding: 20px;
  }

  .intro-lead {
    font-size: 15px;
  }

  .topic-card-body {
    padding: 16px 18px 20px;
  }

  .topic-name {
    font-size: 16px;
  }

  .topic-angle {
    font-size: 14px;
  }

  .topic-audience {
    font-size: 13px;
  }

  .channel-related {
    padding: 14px 16px;
  }

  .channel-related p {
    font-size: 13px;
    line-height: 1.6;
  }

  .timeline-list {
    padding-left: 20px;
  }

  .timeline-item {
    padding: 16px 18px;
    margin-bottom: 16px;
  }

  .timeline-item::before {
    left: -27px;
    width: 10px;
    height: 10px;
  }

  .timeline-meta {
    gap: 8px;
  }

  .timeline-date {
    font-size: 13px;
  }

  .timeline-tag {
    font-size: 12px;
    padding: 1px 8px;
  }

  .timeline-title {
    font-size: 15px;
  }

  .timeline-desc {
    font-size: 14px;
  }

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

  .step-item {
    grid-template-columns: 44px minmax(0, 1fr);
    gap: 14px;
    padding: 18px;
  }

  .step-number {
    width: 40px;
    height: 40px;
    font-size: 17px;
  }

  .step-content h3 {
    font-size: 16px;
  }

  .step-content p {
    font-size: 14px;
  }

  .tips-box {
    padding: 16px 18px;
  }

  .tips-list li {
    font-size: 14px;
  }

  .boundary-note {
    padding: 20px;
  }

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

  .content-media img {
    height: 160px;
  }

  .faq-item summary {
    padding: 14px 16px;
    padding-right: 36px;
    font-size: 14px;
  }

  .faq-answer {
    padding: 12px 16px 14px;
    font-size: 14px;
  }

  .faq-bottom-card {
    padding: 20px;
  }

  .scope-items,
  .not-provided-items {
    grid-template-columns: minmax(0, 1fr);
    gap: 12px;
  }

  .scope-item,
  .not-provided-item {
    padding: 16px 18px;
  }

  .organization-content {
    gap: 16px;
  }

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

  .boundary-table {
    font-size: 13px;
  }

  .boundary-table th,
  .boundary-table td {
    padding: 10px 12px;
  }

  .boundary-table thead {
    display: none;
  }

  .boundary-table tbody {
    display: block;
  }

  .boundary-table tbody tr {
    display: block;
    border-bottom: 2px solid var(--color-border);
    padding: 8px 0;
  }

  .boundary-table tbody tr:last-child {
    border-bottom: none;
  }

  .boundary-table tbody th {
    display: block;
    width: 100%;
    background-color: var(--color-bg);
    font-size: 14px;
    padding: 8px 12px;
    border-bottom: 1px solid var(--color-border-light);
  }

  .boundary-table tbody td {
    display: block;
    width: 100%;
    padding: 8px 12px;
    border-bottom: none;
  }

  .about-intro {
    padding: 20px;
    gap: 20px;
  }

  .about-intro-media img {
    height: 180px;
  }

  .function-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 14px;
  }

  .function-card {
    padding: 18px 20px;
  }

  .system-list {
    grid-template-columns: minmax(0, 1fr);
    gap: 12px;
  }

  .system-item {
    padding: 16px 18px;
  }

  .feedback-options {
    grid-template-columns: minmax(0, 1fr);
    gap: 14px;
  }

  .feedback-card {
    padding: 18px 20px;
  }

  .feedback-note {
    padding: 14px 16px;
    font-size: 13px;
  }

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

  .error-section {
    padding: 32px 20px;
  }

  .error-code {
    font-size: 48px;
  }

  .error-section h1 {
    font-size: 20px;
  }

  .error-desc {
    font-size: 14px;
  }

  .error-links {
    flex-direction: column;
    align-items: stretch;
    gap: 8px;
  }

  .error-links a {
    text-align: center;
  }
}

/* ==========================================================================
   Responsive - 小屏手机（400px 以下）
   ========================================================================== */

@media (max-width: 400px) {
  .brand-name {
    font-size: 18px;
  }

  .nav-list a {
    font-size: 14px;
    padding: 10px 10px;
  }

  .hero-title {
    font-size: 22px;
  }

  .section-head .section-title {
    font-size: 19px;
  }

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

  .step-item {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .step-number {
    width: 36px;
    height: 36px;
    font-size: 16px;
  }

  .footer-inner {
    padding: 32px 16px 20px;
  }
}

/* ==========================================================================
   动效增强（不阻塞初始可见性）
   ========================================================================== */

@media (prefers-reduced-motion: no-preference) {
  .topic-card,
  .related-card {
    transition: box-shadow var(--transition), transform var(--transition);
  }

  .topic-card:hover,
  .related-card:hover {
    transform: translateY(-3px);
  }

  .nav-list a {
    transition: background-color var(--transition), color var(--transition);
  }

  .faq-item summary {
    transition: background-color var(--transition);
  }
}

/* 程序验收反馈：移动端正文优先 */
@media (max-width: 768px) {
  .site-main :is(.page-content, .main-content, .content-main) {
    order: 1;
  }

  .site-main :is(aside, .sidebar) {
    order: 2;
  }
}