/* ============================================================
   BASE — 全局基础样式
   ============================================================ */
:root {
  --color-white: #ffffff;
  --color-gray-50: #f5f7fa;
  --color-gray-100: #edf2f7;
  --color-gray-200: #e2e8f0;
  --color-gray-300: #cbd5e0;
  --color-gray-400: #a0aec0;
  --color-gray-500: #718096;
  --color-gray-600: #4a5568;
  --color-gray-700: #2d3748;
  --color-gray-800: #1a202c;
  --color-blue-500: #3182ce;
  --color-blue-600: #2b6cb0;
  --color-blue-700: #2c5282;
  --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --container-width: 1200px;
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.1);
  --transition-base: 0.2s ease;
}

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

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

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-gray-700);
  background-color: var(--color-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a {
  color: var(--color-blue-600);
  text-decoration: none;
  transition: color var(--transition-base);
}

a:hover {
  color: var(--color-blue-700);
}

ul,
ol {
  list-style: none;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-gray-800);
}

h1 {
  font-size: 28px;
}

h2 {
  font-size: 22px;
}

h3 {
  font-size: 18px;
}

p {
  margin-bottom: 12px;
}

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

/* ============================================================
   LAYOUT — 全站布局骨架
   ============================================================ */
.site-body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.site-header {
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-gray-200);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand-logo {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.brand-name {
  font-size: 20px;
  font-weight: 700;
  color: var(--color-blue-600);
  letter-spacing: 0;
}

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

.site-nav .nav-list li a {
  display: block;
  padding: 8px 16px;
  font-size: 15px;
  font-weight: 500;
  color: var(--color-gray-600);
  border-radius: var(--radius-sm);
  transition: color var(--transition-base), background-color var(--transition-base);
}

.site-nav .nav-list li a:hover {
  color: var(--color-blue-600);
  background-color: var(--color-gray-50);
}

.site-nav .nav-list li a.is-current {
  color: var(--color-blue-600);
  background-color: var(--color-gray-50);
  font-weight: 600;
}

.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;
  position: relative;
  width: 24px;
  height: 2px;
  background-color: var(--color-gray-700);
  transition: background-color var(--transition-base);
}

.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: "";
  position: absolute;
  left: 0;
  width: 24px;
  height: 2px;
  background-color: var(--color-gray-700);
  transition: transform var(--transition-base);
}

.nav-toggle-icon::before {
  top: -7px;
}

.nav-toggle-icon::after {
  top: 7px;
}

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

.nav-toggle[aria-expanded="true"] .nav-toggle-icon::before {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-icon::after {
  transform: translateY(-7px) rotate(-45deg);
}

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

.site-footer {
  background-color: var(--color-gray-800);
  color: var(--color-gray-400);
  margin-top: auto;
}

.footer-inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 48px 24px 24px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
}

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

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

.footer-col ul li a {
  color: var(--color-gray-400);
  font-size: 14px;
  transition: color var(--transition-base);
}

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

.footer-bottom {
  border-top: 1px solid var(--color-gray-700);
  padding-top: 16px;
  margin-top: 32px;
  text-align: center;
}

.footer-bottom p {
  font-size: 13px;
  margin-bottom: 4px;
}

/* ============================================================
   COMPONENTS — 通用组件
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 24px;
  font-size: 15px;
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: background-color var(--transition-base), color var(--transition-base), border-color var(--transition-base);
  cursor: pointer;
  border: 1px solid transparent;
  min-height: 44px;
}

.btn-primary {
  background-color: var(--color-blue-600);
  color: var(--color-white);
}

.btn-primary:hover {
  background-color: var(--color-blue-700);
  color: var(--color-white);
}

.btn-secondary {
  background-color: transparent;
  color: var(--color-blue-600);
  border-color: var(--color-blue-600);
}

.btn-secondary:hover {
  background-color: var(--color-gray-50);
  color: var(--color-blue-700);
  border-color: var(--color-blue-700);
}

.section-block {
  padding: 56px 24px;
}

.section-block > h2 {
  text-align: center;
  margin-bottom: 8px;
}

.section-intro {
  text-align: center;
  color: var(--color-gray-500);
  max-width: 640px;
  margin: 0 auto 32px;
}

.section-link {
  display: inline-flex;
  align-items: center;
  font-weight: 500;
  font-size: 15px;
}

.section-link::after {
  content: "→";
  margin-left: 4px;
  transition: transform var(--transition-base);
}

.section-link:hover::after {
  transform: translateX(4px);
}

/* 卡片通用 */
.topic-card,
.channel-card,
.guide-entry-card {
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: box-shadow var(--transition-base), transform var(--transition-base);
}

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

/* FAQ 手风琴 */
.faq-item {
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-md);
  margin-bottom: 12px;
  overflow: hidden;
}

.faq-item summary {
  padding: 16px 20px;
  font-size: 15px;
  font-weight: 500;
  color: var(--color-gray-700);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  transition: color var(--transition-base);
}

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

.faq-item summary::after {
  content: "+";
  font-size: 20px;
  font-weight: 400;
  color: var(--color-gray-400);
  flex-shrink: 0;
  transition: transform var(--transition-base);
}

.faq-item[open] summary {
  color: var(--color-blue-600);
}

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

.faq-item .faq-answer {
  padding: 0 20px 16px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-gray-600);
}

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

/* 图片容器 */
figure {
  margin: 0;
}

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

/* ============================================================
   PAGES — 首页
   ============================================================ */
/* 焦点区 */
.hero-section {
  background-color: var(--color-gray-50);
  padding: 64px 24px;
}

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

.hero-media .hero-figure {
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.hero-media .hero-figure img {
  width: 100%;
  height: 360px;
  object-fit: cover;
}

.hero-content h1 {
  font-size: 32px;
  margin-bottom: 12px;
}

.hero-subtitle {
  font-size: 18px;
  color: var(--color-blue-600);
  font-weight: 500;
  margin-bottom: 12px;
}

.hero-description {
  color: var(--color-gray-500);
  margin-bottom: 24px;
}

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

/* 频道分类导航带 */
.channels-nav-section {
  background-color: var(--color-white);
}

.channel-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-bottom: 24px;
}

.channel-tag {
  display: inline-flex;
  align-items: center;
  padding: 10px 20px;
  background-color: var(--color-gray-50);
  border: 1px solid var(--color-gray-200);
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  color: var(--color-gray-600);
  transition: background-color var(--transition-base), color var(--transition-base), border-color var(--transition-base);
  min-height: 44px;
}

.channel-tag:hover {
  background-color: var(--color-blue-600);
  color: var(--color-white);
  border-color: var(--color-blue-600);
}

.channels-nav-section > p:last-child {
  text-align: center;
}

/* 专题推荐区 */
.topics-section {
  background-color: var(--color-gray-50);
}

.topics-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  max-width: var(--container-width);
  margin: 0 auto;
}

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

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

.topics-grid .topic-card h3 {
  padding: 16px 20px 4px;
}

.topics-grid .topic-card p {
  padding: 0 20px;
  font-size: 14px;
  color: var(--color-gray-500);
  flex: 1;
}

.topics-grid .topic-card .card-link {
  display: inline-flex;
  align-items: center;
  padding: 8px 20px 16px;
  font-size: 14px;
  font-weight: 500;
  color: var(--color-blue-600);
}

.topics-grid .topic-card .card-link::after {
  content: "→";
  margin-left: 4px;
}

/* 观看指南入口 */
.guide-entry-section {
  background-color: var(--color-white);
}

.guide-entry-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  max-width: var(--container-width);
  margin: 0 auto;
}

.guide-entry-card {
  padding: 32px;
  text-align: center;
}

.guide-entry-card h3 {
  margin-bottom: 12px;
}

.guide-entry-card p {
  color: var(--color-gray-500);
  font-size: 14px;
  margin-bottom: 20px;
}

/* 深度解读入口 */
.insights-section {
  background-color: var(--color-gray-50);
}

.insights-list {
  max-width: var(--container-width);
  margin: 0 auto;
}

.insight-item {
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-md);
  padding: 24px;
  margin-bottom: 16px;
  transition: box-shadow var(--transition-base);
}

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

.insight-item h3 {
  margin-bottom: 8px;
}

.insight-item h3 a {
  color: var(--color-gray-800);
}

.insight-item h3 a:hover {
  color: var(--color-blue-600);
}

.insight-item p {
  font-size: 14px;
  color: var(--color-gray-500);
  margin-bottom: 0;
}

/* 常见问题入口 */
.faq-entry-section {
  background-color: var(--color-white);
}

.faq-preview {
  max-width: 800px;
  margin: 0 auto 24px;
}

.faq-entry-section > p:last-child {
  text-align: center;
}

/* ============================================================
   PAGES — 内页通用
   ============================================================ */
.inner-main {
  background-color: var(--color-gray-50);
}

.inner-main > .breadcrumb,
.inner-main > .page-header {
  max-width: var(--container-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

.breadcrumb {
  padding-top: 24px;
  font-size: 14px;
  color: var(--color-gray-500);
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.breadcrumb a {
  color: var(--color-gray-500);
}

.breadcrumb a:hover {
  color: var(--color-blue-600);
}

.breadcrumb-sep {
  color: var(--color-gray-400);
}

.breadcrumb-current {
  color: var(--color-gray-700);
  font-weight: 500;
}

.page-header {
  padding-top: 16px;
  padding-bottom: 32px;
}

.page-title {
  font-size: 28px;
  margin-bottom: 8px;
}

.page-description {
  color: var(--color-gray-500);
  font-size: 15px;
  max-width: 720px;
}

/* ============================================================
   PAGES — 频道分类页
   ============================================================ */
.channels-section,
.channel-intro-section,
.channels-related {
  max-width: var(--container-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

.channels-section {
  padding-bottom: 48px;
}

.channels-section > h2 {
  margin-bottom: 24px;
}

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

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

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

.channel-info {
  padding: 20px;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.channel-info h3 {
  margin-bottom: 8px;
  font-size: 17px;
}

.channel-info p {
  font-size: 14px;
  color: var(--color-gray-500);
  flex: 1;
  margin-bottom: 12px;
}

.channel-info a {
  font-size: 14px;
  font-weight: 500;
}

.channel-intro-section {
  background-color: var(--color-white);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-gray-200);
  padding: 32px;
  margin-bottom: 48px;
}

.channel-intro-section h2 {
  margin-bottom: 16px;
}

.channel-intro-section p {
  font-size: 15px;
  color: var(--color-gray-600);
  margin-bottom: 12px;
}

.channels-related {
  background-color: var(--color-white);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-gray-200);
  padding: 32px;
  margin-bottom: 48px;
}

.channels-related h2 {
  margin-bottom: 16px;
}

.channels-related ul li {
  margin-bottom: 8px;
}

.channels-related ul li a {
  font-size: 15px;
}

/* ============================================================
   PAGES — 内容专题页
   ============================================================ */
.topic-list-section,
.topic-summary-section,
.topic-guide-note {
  max-width: var(--container-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

.topic-list-section {
  padding-bottom: 48px;
}

.topic-list-section > h2,
.topic-list-section > p {
  margin-bottom: 16px;
}

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

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

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

.topic-card-body {
  padding: 20px;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.topic-card-body h3 {
  margin-bottom: 8px;
  font-size: 17px;
}

.topic-card-body p {
  font-size: 14px;
  color: var(--color-gray-500);
  flex: 1;
  margin-bottom: 12px;
}

.topic-card-body a {
  font-size: 14px;
  font-weight: 500;
}

.topic-summary-section {
  background-color: var(--color-white);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-gray-200);
  padding: 32px;
  margin-bottom: 48px;
}

.topic-summary-section > h2 {
  margin-bottom: 16px;
}

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

.summary-item {
  padding: 20px;
  background-color: var(--color-gray-50);
  border-radius: var(--radius-md);
}

.summary-item h3 {
  font-size: 16px;
  margin-bottom: 8px;
}

.summary-item p {
  font-size: 14px;
  color: var(--color-gray-500);
  margin-bottom: 0;
}

.topic-guide-note {
  background-color: var(--color-white);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-gray-200);
  padding: 32px;
  margin-bottom: 48px;
}

.topic-guide-note h2 {
  margin-bottom: 16px;
}

.topic-guide-note p {
  font-size: 15px;
  color: var(--color-gray-600);
}

.topic-guide-note p a {
  display: inline-flex;
  margin-right: 16px;
  font-weight: 500;
}

/* ============================================================
   PAGES — 实用指南页
   ============================================================ */
.guide-layout {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 24px 48px;
}

.guide-section {
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  padding: 32px;
  margin-bottom: 24px;
}

.guide-section .section-head {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 16px;
}

.guide-section .section-head h2 {
  margin-bottom: 0;
}

.guide-section .step-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background-color: var(--color-blue-600);
  color: var(--color-white);
  font-size: 18px;
  font-weight: 700;
  border-radius: 50%;
  flex-shrink: 0;
}

.guide-section .section-lead {
  font-size: 15px;
  color: var(--color-gray-500);
  margin-bottom: 24px;
}

.guide-content-block {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  align-items: start;
}

.guide-figure {
  border-radius: var(--radius-md);
  overflow: hidden;
}

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

.guide-figure figcaption {
  padding: 8px 0;
  font-size: 13px;
  color: var(--color-gray-500);
  text-align: center;
}

.guide-text p {
  font-size: 15px;
  color: var(--color-gray-600);
  margin-bottom: 12px;
}

.guide-text a {
  font-weight: 500;
}

.guide-summary {
  background-color: var(--color-gray-50);
  border-radius: var(--radius-lg);
  padding: 24px;
  margin-top: 32px;
}

.guide-summary h3 {
  margin-bottom: 12px;
}

.guide-summary p {
  font-size: 15px;
  color: var(--color-gray-600);
  margin-bottom: 8px;
}

/* ============================================================
   PAGES — 深度解读页
   ============================================================ */
.page-layout {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 24px 48px;
}

.insights-article {
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  padding: 40px;
}

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

.insight-section h2 {
  font-size: 22px;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--color-gray-100);
}

.insight-section p {
  font-size: 15px;
  color: var(--color-gray-600);
  margin-bottom: 16px;
}

.insight-figure {
  border-radius: var(--radius-md);
  overflow: hidden;
  margin: 24px 0;
}

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

.insight-figure figcaption {
  padding: 8px 0;
  font-size: 13px;
  color: var(--color-gray-500);
  text-align: center;
}

.attention-list {
  margin: 16px 0;
}

.attention-list li {
  position: relative;
  padding-left: 20px;
  font-size: 15px;
  color: var(--color-gray-600);
  margin-bottom: 8px;
}

.attention-list li::before {
  content: "·";
  position: absolute;
  left: 4px;
  color: var(--color-blue-600);
  font-weight: 700;
}

.related-links {
  background-color: var(--color-gray-50);
  border-radius: var(--radius-md);
  padding: 24px;
  margin-top: 32px;
}

.related-links h3 {
  margin-bottom: 16px;
  font-size: 16px;
}

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

.related-links ul li a {
  font-size: 14px;
}

/* ============================================================
   PAGES — 常见问题页
   ============================================================ */
.faq-section {
  max-width: 800px;
  margin: 0 auto 48px;
  padding: 0 24px;
}

.faq-section .section-title {
  font-size: 20px;
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--color-gray-100);
}

.content-media {
  border-radius: var(--radius-md);
  overflow: hidden;
  margin-bottom: 20px;
}

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

.content-media figcaption {
  padding: 8px 0;
  font-size: 13px;
  color: var(--color-gray-500);
  text-align: center;
}

.faq-list {
  margin-bottom: 24px;
}

.faq-help {
  max-width: 800px;
  margin: 0 auto 48px;
  padding: 0 24px;
  background-color: var(--color-white);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-gray-200);
  padding: 32px;
}

.faq-help h2 {
  margin-bottom: 16px;
}

.faq-help p {
  font-size: 15px;
  color: var(--color-gray-600);
}

.faq-help p a {
  display: inline-flex;
  margin-right: 16px;
  font-weight: 500;
}

/* ============================================================
   PAGES — 404 页面
   ============================================================ */
.error-main {
  background-color: var(--color-gray-50);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 80px 24px;
}

.error-section {
  text-align: center;
  max-width: 600px;
}

.error-code {
  font-size: 96px;
  font-weight: 700;
  color: var(--color-blue-600);
  line-height: 1;
  margin-bottom: 16px;
}

.error-section h1 {
  font-size: 28px;
  margin-bottom: 16px;
}

.error-desc {
  font-size: 16px;
  color: var(--color-gray-500);
  margin-bottom: 32px;
}

.error-actions {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.error-help {
  font-size: 14px;
  color: var(--color-gray-400);
}

/* ============================================================
   RESPONSIVE — 响应式规则
   ============================================================ */
@media (max-width: 1024px) {
  .channel-group,
  .topic-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .hero-section {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .hero-media .hero-figure img {
    height: 300px;
  }
}

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

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background-color: var(--color-white);
    border-bottom: 1px solid var(--color-gray-200);
    box-shadow: var(--shadow-md);
    display: block;
  }

  .site-nav .nav-list {
    display: none;
    flex-direction: column;
    padding: 8px 16px;
    gap: 0;
  }

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

  .site-nav .nav-list li {
    width: 100%;
  }

  .site-nav .nav-list li a {
    padding: 14px 16px;
    border-radius: var(--radius-sm);
  }

  .footer-inner {
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
    padding: 32px 16px 16px;
  }

  .section-block {
    padding: 40px 16px;
  }

  .hero-section {
    padding: 40px 16px;
  }

  .hero-content h1 {
    font-size: 24px;
  }

  .hero-media .hero-figure img {
    height: 240px;
  }

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

  .guide-content-block {
    grid-template-columns: 1fr;
    gap: 16px;
  }

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

  .inner-main > .breadcrumb,
  .inner-main > .page-header,
  .channels-section,
  .channel-intro-section,
  .channels-related,
  .topic-list-section,
  .topic-summary-section,
  .topic-guide-note,
  .guide-layout,
  .page-layout,
  .faq-section,
  .faq-help {
    padding-left: 16px;
    padding-right: 16px;
  }

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

  .channel-intro-section,
  .channels-related,
  .topic-summary-section,
  .topic-guide-note,
  .guide-section,
  .insights-article,
  .faq-help {
    padding: 24px 16px;
  }

  .insights-article {
    padding: 24px 16px;
  }

  .error-code {
    font-size: 72px;
  }
}

@media (max-width: 480px) {
  .channel-group,
  .topic-grid {
    grid-template-columns: 1fr;
  }

  .brand-name {
    font-size: 17px;
  }

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

  .channel-tags {
    gap: 8px;
  }

  .channel-tag {
    padding: 8px 14px;
    font-size: 13px;
  }

  .hero-cta {
    flex-direction: column;
    align-items: stretch;
  }

  .hero-cta .btn {
    width: 100%;
  }

  .error-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .error-actions .btn {
    width: 100%;
  }
}