/* ============================================================
   base — 基础变量、Reset、全局字体与颜色
   ============================================================ */
:root {
  --color-bg: #f5f7f8;
  --color-primary: #20b2aa;
  --color-primary-dark: #1a8f89;
  --color-text: #2c3e50;
  --color-white: #ffffff;
  --color-border: #e0e0e0;
  --color-muted: #6b7a8d;
  --color-muted-light: #9aa7b5;
  --color-dark: #1e2a38;
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", sans-serif;
  --font-size-base: 16px;
  --line-height-base: 1.6;
  --container-width: 1200px;
  --container-padding: 20px;
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --shadow-card: 0 1px 3px rgba(44, 62, 80, 0.08);
  --shadow-hover: 0 4px 12px rgba(44, 62, 80, 0.12);
  --transition-base: 0.2s ease;
  --breakpoint-mobile: 768px;
}

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

html {
  font-size: var(--font-size-base);
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: var(--line-height-base);
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

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

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

ul,
ol {
  list-style: none;
}

button {
  font-family: inherit;
  font-size: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

/* ============================================================
   layout — 全站统一骨架：页头、主容器、页脚
   ============================================================ */
.site-header {
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
  height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

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

.brand-name {
  font-size: 22px;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: 0;
}

.brand-tagline {
  font-size: 13px;
  color: var(--color-muted);
  display: none;
}

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

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

.nav-list li a {
  display: block;
  padding: 8px 16px;
  font-size: 15px;
  font-weight: 500;
  color: var(--color-text);
  border-radius: var(--radius-sm);
  line-height: 1.4;
}

.nav-list li a:hover {
  color: var(--color-primary);
  background-color: rgba(32, 178, 170, 0.08);
}

.nav-list li a.is-current {
  color: var(--color-primary);
  font-weight: 600;
  background-color: rgba(32, 178, 170, 0.1);
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
}

.nav-toggle:hover {
  background-color: rgba(32, 178, 170, 0.08);
}

.nav-toggle-icon,
.nav-toggle-icon::before,
.nav-toggle-icon::after {
  display: block;
  width: 20px;
  height: 2px;
  background-color: var(--color-text);
  border-radius: 2px;
  position: relative;
  transition: transform var(--transition-base);
}

.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: "";
  position: absolute;
  left: 0;
}

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

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

.nav-toggle[aria-expanded="true"] .nav-toggle-icon {
  background-color: transparent;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-icon::before {
  transform: rotate(45deg);
  top: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-icon::after {
  transform: rotate(-45deg);
  top: 0;
}

.site-main {
  flex: 1 0 auto;
  width: 100%;
}

.site-footer {
  background-color: var(--color-dark);
  color: #c8d1dc;
  margin-top: 60px;
}

.footer-index {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 48px var(--container-padding) 32px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
}

.footer-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: 14px;
}

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

.footer-links li a {
  font-size: 14px;
  color: #a8b3bf;
}

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

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding: 20px var(--container-padding);
  text-align: center;
}

.footer-bottom p {
  font-size: 13px;
  color: #8a97a5;
  line-height: 1.5;
}

.footer-copy {
  margin-bottom: 4px;
}

/* ============================================================
   components — 通用组件：面包屑、页标题、章节标题、卡片等
   ============================================================ */
.breadcrumb {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 16px var(--container-padding) 0;
  font-size: 14px;
  color: var(--color-muted);
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

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

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

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

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

.page-header {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 20px var(--container-padding) 8px;
}

.page-title {
  font-size: 32px;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.3;
  margin-bottom: 8px;
}

.page-description {
  font-size: 16px;
  color: var(--color-muted);
  max-width: 720px;
}

.section-title {
  font-size: 24px;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.3;
  margin-bottom: 8px;
}

.section-intro {
  font-size: 15px;
  color: var(--color-muted);
  margin-bottom: 24px;
  max-width: 720px;
}

.section-desc {
  font-size: 15px;
  color: var(--color-muted);
  margin-bottom: 24px;
  max-width: 720px;
}

/* 通用卡片 */
.topic-card,
.channel-card,
.guide-card,
.tip-card {
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  transition: box-shadow var(--transition-base),
    transform var(--transition-base);
}

.topic-card:hover,
.channel-card:hover,
.guide-card:hover,
.tip-card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}

/* ============================================================
   pages/index — 首页专属
   ============================================================ */
.home-main {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

/* 首屏步骤区 */
.hero-steps {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
  padding: 48px 0 40px;
}

.hero-visual {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
}

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

.hero-content h1 {
  font-size: 32px;
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-text);
  margin-bottom: 12px;
}

.hero-lead {
  font-size: 16px;
  color: var(--color-muted);
  line-height: 1.7;
  margin-bottom: 28px;
}

.step-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-bottom: 28px;
}

.step-item {
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 16px;
}

.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background-color: var(--color-primary);
  color: var(--color-white);
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 10px;
}

.step-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 4px;
}

.step-desc {
  font-size: 13px;
  color: var(--color-muted);
  line-height: 1.5;
}

.cta-link {
  display: inline-block;
  padding: 10px 24px;
  background-color: var(--color-primary);
  color: var(--color-white);
  font-size: 15px;
  font-weight: 500;
  border-radius: var(--radius-md);
  transition: background-color var(--transition-base);
}

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

/* 频道分类导航带 */
.channel-strip {
  padding: 32px 0;
  border-top: 1px solid var(--color-border);
}

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

.channel-tag {
  display: inline-block;
  padding: 8px 20px;
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  color: var(--color-text);
  transition: all var(--transition-base);
}

.channel-tag:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background-color: rgba(32, 178, 170, 0.06);
}

/* 专题推荐区 */
.topics-preview {
  padding: 32px 0;
}

.topic-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr 1fr;
  gap: 20px;
}

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

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

.topic-card-main .topic-img {
  height: 240px;
}

.topic-body {
  padding: 16px;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.topic-name {
  font-size: 17px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 8px;
}

.topic-card-main .topic-name {
  font-size: 19px;
}

.topic-desc {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.6;
  margin-bottom: 12px;
  flex: 1;
}

.topic-link {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-primary);
  align-self: flex-start;
}

.topic-link:hover {
  color: var(--color-primary-dark);
}

/* 最新更新列表 */
.latest-updates {
  padding: 32px 0;
  border-top: 1px solid var(--color-border);
}

.update-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.update-item {
  border-bottom: 1px solid var(--color-border);
}

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

.update-link {
  display: block;
  padding: 16px 8px;
  transition: background-color var(--transition-base);
}

.update-link:hover {
  background-color: rgba(32, 178, 170, 0.04);
}

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

.update-meta {
  display: block;
  font-size: 13px;
  color: var(--color-muted-light);
  margin-bottom: 4px;
}

.update-desc {
  display: block;
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.5;
}

/* 观看指南入口 */
.guide-entry {
  padding: 32px 0;
}

.guide-card-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.guide-card {
  padding: 24px;
}

.guide-card-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 8px;
}

.guide-card-text {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.6;
  margin-bottom: 16px;
}

.guide-card-link {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-primary);
}

/* 信息来源与反馈 */
.info-feedback {
  padding: 32px 0;
  border-top: 1px solid var(--color-border);
}

.info-text {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.7;
  margin-bottom: 16px;
}

.info-text strong {
  color: var(--color-text);
}

.feedback-links {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.feedback-links a {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-primary);
}

/* ============================================================
   pages/channels — 频道分类页
   ============================================================ */
.inner-main {
  padding-bottom: 40px;
}

.channel-grid-section {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 24px var(--container-padding) 8px;
}

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

.channel-card {
  display: flex;
  flex-direction: column;
}

.channel-card-media {
  overflow: hidden;
}

.channel-card-media img {
  width: 100%;
  height: 160px;
  object-fit: cover;
}

.channel-card-body {
  padding: 16px;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.channel-name {
  font-size: 17px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 8px;
}

.channel-desc {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.6;
  margin-bottom: 12px;
  flex: 1;
}

.channel-link {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-primary);
  align-self: flex-start;
}

.channel-note-section {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 24px var(--container-padding) 0;
}

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

.channel-note-content p {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.7;
  margin-bottom: 12px;
}

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

/* ============================================================
   pages/guide — 观看指南页
   ============================================================ */
.guide-steps,
.guide-topics,
.guide-tips,
.info-note {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 24px var(--container-padding) 0;
}

.guide-steps .step-list,
.guide-topics .step-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-bottom: 24px;
}

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

.guide-steps .step-num,
.guide-topics .step-num {
  width: 32px;
  height: 32px;
  flex-shrink: 0;
  font-size: 15px;
}

.guide-steps .step-body,
.guide-topics .step-body {
  flex: 1;
}

.guide-steps .step-title,
.guide-topics .step-title {
  font-size: 17px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 6px;
}

.guide-steps .step-body p,
.guide-topics .step-body p {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.7;
}

.guide-figure {
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin: 24px 0;
}

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

.guide-figure figcaption {
  padding: 12px 16px;
  font-size: 13px;
  color: var(--color-muted);
  background-color: var(--color-white);
}

.guide-tips .tip-card {
  padding: 20px;
  margin-bottom: 16px;
}

.tip-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 8px;
}

.guide-tips .tip-card p {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.7;
}

.guide-tips .tip-card p a {
  color: var(--color-primary);
  font-weight: 500;
}

.info-note {
  padding-bottom: 0;
}

.info-note p {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.7;
  margin-bottom: 12px;
}

/* ============================================================
   pages/topics — 内容专题页
   ============================================================ */
.section {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 24px var(--container-padding) 0;
}

.topic-list {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

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

.topic-card-feature .topic-media {
  overflow: hidden;
}

.topic-card-feature .topic-media img {
  width: 100%;
  height: 100%;
  min-height: 220px;
  object-fit: cover;
}

.topic-card-feature .topic-body {
  padding: 24px;
}

.topic-card-feature .topic-name {
  font-size: 20px;
  margin-bottom: 12px;
}

.topic-card-feature .topic-desc {
  font-size: 15px;
  margin-bottom: 12px;
}

.topic-note {
  font-size: 13px;
  color: var(--color-muted-light);
  font-style: italic;
}

.topic-list-hot .topic-card:not(.topic-card-feature) {
  display: grid;
  grid-template-columns: 200px 1fr;
}

.topic-list-hot .topic-card:not(.topic-card-feature) .topic-media {
  overflow: hidden;
}

.topic-list-hot .topic-card:not(.topic-card-feature) .topic-media img {
  width: 100%;
  height: 100%;
  min-height: 140px;
  object-fit: cover;
}

.topic-list-hot .topic-card:not(.topic-card-feature) .topic-body {
  padding: 16px 20px;
}

.topic-list-new {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.topic-item {
  display: flex;
  gap: 16px;
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  transition: box-shadow var(--transition-base);
}

.topic-item:hover {
  box-shadow: var(--shadow-hover);
}

.topic-thumb {
  width: 160px;
  flex-shrink: 0;
  overflow: hidden;
}

.topic-thumb img {
  width: 100%;
  height: 100%;
  min-height: 110px;
  object-fit: cover;
}

.topic-item-body {
  padding: 16px 16px 16px 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.topic-item-body .topic-name {
  font-size: 16px;
  margin-bottom: 4px;
}

.topic-item-body .topic-desc {
  font-size: 13px;
  margin-bottom: 4px;
}

.topic-date {
  font-size: 13px;
  color: var(--color-muted-light);
}

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

.section-topics-tips .tip-card {
  padding: 20px;
}

.section-topics-tips .tip-card p {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.7;
}

.section-feedback {
  padding-bottom: 0;
}

.section-feedback p {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.7;
  margin-bottom: 12px;
}

/* ============================================================
   pages/updates — 更新动态页
   ============================================================ */
.updates-section {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 24px var(--container-padding) 0;
}

.updates-section > h2 {
  font-size: 24px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 8px;
}

.updates-section .update-item {
  display: flex;
  gap: 20px;
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin-bottom: 16px;
  box-shadow: var(--shadow-card);
  transition: box-shadow var(--transition-base);
}

.updates-section .update-item:hover {
  box-shadow: var(--shadow-hover);
}

.update-thumb {
  width: 200px;
  flex-shrink: 0;
  overflow: hidden;
}

.update-thumb img {
  width: 100%;
  height: 100%;
  min-height: 120px;
  object-fit: cover;
}

.update-body {
  padding: 16px 20px 16px 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.update-title {
  font-size: 17px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 6px;
}

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

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

.update-desc {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.6;
  margin-bottom: 6px;
}

.update-date {
  font-size: 13px;
  color: var(--color-muted-light);
}

.updates-more {
  margin-top: 24px;
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.updates-more a {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-primary);
}

.update-note {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 24px var(--container-padding) 0;
}

.update-note h2 {
  font-size: 24px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 8px;
}

.update-note p {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.7;
  margin-bottom: 12px;
}

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

.error-panel {
  text-align: center;
  max-width: 480px;
}

.error-code {
  font-size: 72px;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1;
  margin-bottom: 16px;
}

.error-title {
  font-size: 24px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 12px;
}

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

.error-link {
  display: inline-block;
  padding: 10px 28px;
  background-color: var(--color-primary);
  color: var(--color-white);
  font-size: 15px;
  font-weight: 500;
  border-radius: var(--radius-md);
}

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

/* ============================================================
   responsive — 响应式适配
   ============================================================ */
@media (max-width: 1024px) {
  .topic-grid {
    grid-template-columns: 1fr 1fr;
  }

  .topic-card-main {
    grid-column: 1 / -1;
  }

  .topic-card-main .topic-img {
    height: 260px;
  }

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

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

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

@media (max-width: 768px) {
  .header-inner {
    height: 60px;
  }

  .brand-name {
    font-size: 18px;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-list {
    display: none;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background-color: var(--color-white);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    align-items: stretch;
    padding: 8px 0;
    box-shadow: 0 4px 12px rgba(44, 62, 80, 0.08);
  }

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

  .nav-list li a {
    padding: 12px 20px;
    border-radius: 0;
    font-size: 16px;
  }

  .hero-steps {
    grid-template-columns: 1fr;
    gap: 24px;
    padding: 24px 0;
  }

  .hero-image {
    height: 220px;
  }

  .hero-content h1 {
    font-size: 26px;
  }

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

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

  .topic-card-main {
    grid-column: auto;
  }

  .topic-card-main .topic-img {
    height: 200px;
  }

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

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

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

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

  .topic-list-hot .topic-card:not(.topic-card-feature) {
    grid-template-columns: 1fr;
  }

  .topic-list-hot .topic-card:not(.topic-card-feature) .topic-media img {
    height: 180px;
  }

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

  .topic-thumb {
    width: 120px;
  }

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

  .updates-section .update-item {
    flex-direction: column;
  }

  .update-thumb {
    width: 100%;
  }

  .update-thumb img {
    height: 180px;
  }

  .update-body {
    padding: 12px 16px 16px;
  }

  .footer-index {
    grid-template-columns: 1fr;
    gap: 20px;
    padding: 32px var(--container-padding) 24px;
  }

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

  .site-footer {
    margin-top: 40px;
  }
}