/* ============================================================
   糖心 shuxicheji.com — 整站样式表
   视觉方向：开发者文档风 × 媒体编辑部
   分组：base / layout / components / pages / responsive
   ============================================================ */

/* ============================================================
   Base — 变量、重置、全局字体与颜色
   ============================================================ */
:root {
  --bg-page: #F8FAFC;
  --bg-card: #FFFFFF;
  --bg-soft: #F1F5F9;
  --bg-tint: #F0F9FF;
  --ink-strong: #1E293B;
  --ink-body: #334155;
  --ink-mid: #475569;
  --ink-note: #64748B;
  --ink-faint: #94A3B8;
  --line: #E2E8F0;
  --line-strong: #CBD5E1;
  --accent-blue: #0EA5E9;
  --accent-green: #10B981;
  --accent-blue-dark: #0284C7;
  --accent-green-dark: #059669;
  --accent-blue-soft: rgba(14, 165, 233, 0.08);
  --accent-green-soft: rgba(16, 185, 129, 0.08);
  --radius: 6px;
  --radius-lg: 8px;
  --container: 1200px;
  --content-max: 720px;
  --header-h: 64px;
  --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", "JetBrains Mono", "Fira Code", Consolas, "Roboto Mono", "Courier New", monospace;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.04);
  --shadow-md: 0 4px 16px rgba(15, 23, 42, 0.06);
  --ease: 180ms cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink-body);
  background-color: var(--bg-page);
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--accent-blue-dark);
  text-decoration: none;
  transition: color var(--ease);
}

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

ul, ol {
  list-style: none;
}

h1, h2, h3, h4 {
  color: var(--ink-strong);
  line-height: 1.3;
}

.mono {
  font-family: var(--font-mono);
  font-size: 0.92em;
  letter-spacing: 0;
}

/* ============================================================
   Layout — 全站骨架：页头、导航、页脚、主容器
   ============================================================ */
.site-body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  background-color: var(--bg-page);
}

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

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

.brand {
  flex-shrink: 0;
}

.brand a {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.brand-name {
  font-size: 19px;
  font-weight: 700;
  color: var(--ink-strong);
  letter-spacing: 0.01em;
}

.brand-tag {
  font-size: 11px;
  color: var(--ink-note);
  margin-top: 2px;
  letter-spacing: 0.02em;
}

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

.site-nav .nav-list li a {
  display: block;
  padding: 6px 14px;
  font-size: 14px;
  font-weight: 500;
  color: var(--ink-mid);
  border-radius: var(--radius);
  line-height: 1.6;
}

.site-nav .nav-list li a:hover {
  color: var(--accent-blue-dark);
  background-color: var(--accent-blue-soft);
}

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

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

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

/* 主内容骨架 */
.site-main {
  flex: 1 0 auto;
  width: 100%;
}

.site-main.inner-main {
  max-width: var(--container);
  margin: 0 auto;
  padding: 32px 24px 64px;
  width: 100%;
}

/* 页脚 */
.site-footer {
  background-color: #FFFFFF;
  border-top: 1px solid var(--line);
  margin-top: auto;
}

.footer-shell {
  max-width: var(--container);
  margin: 0 auto;
  padding: 48px 24px 32px;
  display: grid;
  grid-template-columns: minmax(280px, 1.6fr) 1fr 1fr minmax(240px, 1.2fr);
  gap: 40px;
}

.footer-brand strong {
  display: block;
  font-size: 17px;
  color: var(--ink-strong);
  margin-bottom: 8px;
}

.footer-boundary {
  font-size: 13px;
  color: var(--ink-note);
  line-height: 1.8;
  max-width: 320px;
}

.footer-column h2 {
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-strong);
  margin-bottom: 14px;
  letter-spacing: 0.02em;
}

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

.footer-column ul li a {
  font-size: 14px;
  color: var(--ink-mid);
  line-height: 1.6;
}

.footer-column ul li a:hover {
  color: var(--accent-blue-dark);
}

.footer-meta {
  font-size: 12px;
  color: var(--ink-faint);
  line-height: 1.8;
}

.footer-meta p {
  margin-bottom: 6px;
}

/* ============================================================
   Components — 通用组件：面包屑、页面标题、section、卡片、表格
   ============================================================ */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--ink-note);
  margin-bottom: 20px;
  flex-wrap: wrap;
}

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

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

.breadcrumb-sep {
  color: var(--ink-faint);
}

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

.page-header {
  margin-bottom: 32px;
  max-width: 860px;
}

.page-title {
  font-size: 30px;
  font-weight: 700;
  color: var(--ink-strong);
  margin-bottom: 10px;
  line-height: 1.25;
}

.page-description {
  font-size: 16px;
  color: var(--ink-mid);
  max-width: 680px;
}

.section-block {
  margin-bottom: 48px;
}

.section-heading {
  margin-bottom: 24px;
}

.section-heading h2,
.section-title {
  font-size: 22px;
  font-weight: 700;
  color: var(--ink-strong);
  margin-bottom: 8px;
  line-height: 1.35;
}

.section-heading .section-intro,
.section-note {
  color: var(--ink-mid);
  font-size: 15px;
  max-width: 720px;
}

.section-kicker {
  display: block;
  font-size: 13px;
  color: var(--accent-blue);
  margin-bottom: 4px;
  font-weight: 500;
}

/* 内页双栏布局 */
.layout-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 48px;
  align-items: start;
}

.layout-shell.sidebar-left {
  grid-template-columns: 260px minmax(0, 1fr);
}

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

.layout-aside {
  min-width: 0;
}

/* ============================================================
   Pages — 首页
   ============================================================ */
.home-main {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

/* 编辑部式首屏 */
.home-hero.editorial-splash {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  gap: 48px;
  padding: 48px 0 40px;
  align-items: center;
}

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

.report-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background-color: var(--accent-green-soft);
  border: 1px solid rgba(16, 185, 129, 0.25);
  color: var(--accent-green-dark);
  font-size: 12px;
  font-weight: 600;
  padding: 4px 12px;
  border-radius: 4px;
  margin-bottom: 18px;
}

.report-label .mono {
  font-size: 11px;
}

.hero-copy h1 {
  font-size: 38px;
  font-weight: 800;
  line-height: 1.2;
  color: var(--ink-strong);
  margin-bottom: 14px;
  max-width: 560px;
}

.hero-lead {
  font-size: 16px;
  color: var(--ink-mid);
  max-width: 540px;
  margin-bottom: 24px;
}

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

.action-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  font-size: 14px;
  font-weight: 600;
  border-radius: var(--radius);
  line-height: 1.5;
}

.action-link:first-child {
  background-color: var(--accent-blue);
  color: #FFFFFF;
}

.action-link:first-child:hover {
  background-color: var(--accent-blue-dark);
  color: #FFFFFF;
}

.action-link:last-child {
  border: 1px solid var(--line-strong);
  color: var(--ink-strong);
  background-color: #FFFFFF;
}

.action-link:last-child:hover {
  border-color: var(--accent-blue);
  color: var(--accent-blue-dark);
}

.hero-media {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.media-figure {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--line);
  background-color: var(--bg-soft);
  aspect-ratio: 16 / 10;
}

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

.secondary-links {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.secondary-links a {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 12px 14px;
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: border-color var(--ease), box-shadow var(--ease);
}

.secondary-links a:hover {
  border-color: var(--accent-blue);
  box-shadow: var(--shadow-sm);
}

.secondary-link-index {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent-blue);
  flex-shrink: 0;
  line-height: 1.6;
}

.secondary-link-text {
  font-size: 14px;
  color: var(--ink-strong);
  font-weight: 500;
  line-height: 1.5;
}

/* 更新窄带 */
.update-strip {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 12px 16px;
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent-green);
  border-radius: var(--radius);
  margin-bottom: 56px;
  flex-wrap: wrap;
}

.update-version {
  font-size: 13px;
  color: var(--ink-strong);
  flex-shrink: 0;
}

.update-version .mono {
  color: var(--accent-green-dark);
  font-weight: 600;
}

.update-desc {
  font-size: 13px;
  color: var(--ink-note);
}

/* 通用首页 section */
.home-section {
  margin-bottom: 56px;
}

.section-heading h2 {
  font-size: 24px;
}

/* 频道速览 */
.channel-index-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.channel-index-card {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 16px 18px;
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: border-color var(--ease), box-shadow var(--ease);
}

.channel-index-card:hover {
  border-color: var(--accent-blue);
  box-shadow: var(--shadow-sm);
}

.channel-code {
  font-size: 13px;
  color: var(--accent-blue);
  flex-shrink: 0;
  font-weight: 600;
}

.channel-name {
  font-size: 15px;
  font-weight: 600;
  color: var(--ink-strong);
  flex-shrink: 0;
  min-width: 96px;
}

.channel-note {
  font-size: 13px;
  color: var(--ink-note);
  line-height: 1.6;
}

/* 指南步骤条 */
.guide-steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.guide-step {
  padding: 24px 20px;
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
}

.step-number {
  font-size: 13px;
  color: var(--accent-green);
  font-weight: 600;
  margin-bottom: 10px;
}

.guide-step h3 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
}

.guide-step p {
  font-size: 13px;
  color: var(--ink-note);
  margin-bottom: 14px;
  flex-grow: 1;
}

.guide-step a {
  font-size: 13px;
  font-weight: 500;
}

/* 专题预告 */
.topics-teaser {
  display: grid;
  grid-template-columns: minmax(0, 340px) minmax(0, 1fr);
  gap: 40px;
  align-items: start;
}

.teaser-copy h2 {
  font-size: 24px;
  font-weight: 700;
  color: var(--ink-strong);
  margin-bottom: 12px;
}

.teaser-copy p {
  font-size: 15px;
  color: var(--ink-mid);
  margin-bottom: 16px;
}

.teaser-copy a {
  font-weight: 500;
  font-size: 14px;
}

.teaser-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.topic-item {
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  transition: border-color var(--ease), box-shadow var(--ease);
}

.topic-item:hover {
  border-color: var(--accent-blue);
  box-shadow: var(--shadow-sm);
}

.topic-item img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  background-color: var(--bg-soft);
}

.topic-item h3 {
  font-size: 15px;
  font-weight: 600;
  padding: 12px 14px 4px;
}

.topic-item p {
  font-size: 13px;
  color: var(--ink-note);
  padding: 0 14px 14px;
}

/* FAQ 窄带 */
.faq-teaser .section-heading h2 {
  font-size: 22px;
}

.faq-item {
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  margin-bottom: 10px;
}

.faq-item summary {
  padding: 16px 20px;
  font-size: 15px;
  font-weight: 500;
  color: var(--ink-strong);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}

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

.faq-item summary::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--ink-faint);
  flex-shrink: 0;
  transition: transform var(--ease);
}

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

.faq-item[open] summary {
  border-bottom: 1px solid var(--line);
}

.faq-item > p,
.faq-answer {
  padding: 14px 20px 18px;
  font-size: 14px;
  color: var(--ink-mid);
}

.faq-answer p {
  font-size: 14px;
  color: var(--ink-mid);
  margin-bottom: 8px;
}

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

.faq-more-link {
  margin-top: 14px;
  font-size: 14px;
}

/* ============================================================
   Pages — 频道总览 tx/channels.html
   ============================================================ */
.page-channels .page-header {
  margin-bottom: 24px;
}

.channel-overview h2 {
  font-size: 22px;
  font-weight: 700;
  color: var(--ink-strong);
  margin-bottom: 12px;
}

.channel-overview p {
  font-size: 15px;
  color: var(--ink-mid);
  margin-bottom: 12px;
  max-width: 780px;
}

.channel-table-wrap h2 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 8px;
}

.channel-table-wrap > p {
  font-size: 15px;
  color: var(--ink-mid);
  margin-bottom: 16px;
}

.table-scroll {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background-color: #FFFFFF;
}

.channel-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  min-width: 640px;
}

.channel-table th {
  background-color: var(--bg-soft);
  color: var(--ink-strong);
  font-weight: 600;
  text-align: left;
  padding: 12px 16px;
  border-bottom: 1px solid var(--line);
  white-space: nowrap;
}

.channel-table td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--line);
  color: var(--ink-body);
  vertical-align: top;
}

.channel-table tr:last-child td {
  border-bottom: none;
}

.channel-table tbody tr:hover {
  background-color: var(--bg-tint);
}

.channel-cards-section h2 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 8px;
}

.channel-cards-section > p {
  font-size: 15px;
  color: var(--ink-mid);
  margin-bottom: 24px;
}

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

.channel-card {
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: border-color var(--ease), box-shadow var(--ease);
}

.channel-card:hover {
  border-color: var(--accent-blue);
  box-shadow: var(--shadow-sm);
}

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

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

.channel-card h3 {
  font-size: 16px;
  font-weight: 600;
  padding: 14px 16px 4px;
  display: flex;
  align-items: baseline;
  gap: 8px;
}

.channel-num {
  font-size: 12px;
  color: var(--accent-blue);
}

.channel-card > p {
  font-size: 13px;
  color: var(--ink-mid);
  padding: 0 16px;
  margin-bottom: 8px;
}

.channel-card .card-tip {
  font-size: 12px;
  color: var(--ink-note);
  border-top: 1px dashed var(--line);
  margin: auto 16px 0;
  padding: 10px 0 14px;
}

/* 选频道建议 */
.channel-advice h2 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 20px;
}

.advice-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  gap: 40px;
  align-items: start;
}

.advice-main {
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 24px 28px;
}

.advice-main h3 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
}

.advice-main p {
  font-size: 14px;
  color: var(--ink-mid);
  margin-bottom: 18px;
}

.advice-main h3:last-of-type {
  margin-top: 8px;
}

.channel-aside {
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 20px;
}

.channel-aside h3 {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--ink-strong);
}

.aside-links li {
  margin-bottom: 10px;
}

.aside-links li a {
  font-size: 14px;
  font-weight: 500;
  display: block;
}

.aside-links li span {
  display: block;
  font-size: 12px;
  color: var(--ink-note);
  margin-top: 2px;
  line-height: 1.5;
}

.aside-note {
  font-size: 12px;
  color: var(--ink-note);
  border-top: 1px dashed var(--line);
  padding-top: 12px;
  margin-top: 12px;
  line-height: 1.7;
}

/* ============================================================
   Pages — 专题片单 tx/topics.html
   ============================================================ */
.page-topics .layout-shell,
.page-topics .layout-main,
.page-topics .layout-aside {
  display: block;
}

.topics-intro {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 420px);
  gap: 40px;
  align-items: center;
  margin-bottom: 48px;
}

.intro-copy .section-title {
  font-size: 22px;
  margin-bottom: 12px;
}

.intro-copy p {
  font-size: 15px;
  color: var(--ink-mid);
  margin-bottom: 12px;
}

.intro-media {
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--line);
}

.intro-media img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

.intro-media figcaption {
  font-size: 12px;
  color: var(--ink-note);
  padding: 8px 12px;
  background-color: #FFFFFF;
}

.topic-angles {
  margin-bottom: 48px;
}

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

.angle-item {
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 24px 20px;
}

.angle-number {
  display: block;
  font-size: 14px;
  color: var(--accent-blue);
  font-weight: 600;
  margin-bottom: 8px;
}

.angle-item h3 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
}

.angle-item p {
  font-size: 14px;
  color: var(--ink-mid);
}

.topic-compare {
  margin-bottom: 48px;
}

.compare-table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background-color: #FFFFFF;
}

.compare-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  min-width: 640px;
}

.compare-table th {
  background-color: var(--bg-soft);
  color: var(--ink-strong);
  font-weight: 600;
  text-align: left;
  padding: 12px 16px;
  border-bottom: 1px solid var(--line);
}

.compare-table td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--line);
  color: var(--ink-body);
  vertical-align: top;
}

.compare-table tr:last-child td {
  border-bottom: none;
}

.topic-lists {
  margin-bottom: 48px;
}

.topic-lists .section-heading p {
  margin-bottom: 4px;
}

.playlist-items {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.playlist-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  padding: 18px 20px;
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: border-color var(--ease);
}

.playlist-item:hover {
  border-color: var(--accent-blue);
}

.playlist-tag {
  font-size: 12px;
  color: var(--accent-green-dark);
  background-color: var(--accent-green-soft);
  padding: 3px 10px;
  border-radius: 4px;
  flex-shrink: 0;
  margin-top: 2px;
}

.playlist-info h3 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 4px;
}

.playlist-info p {
  font-size: 14px;
  color: var(--ink-mid);
  margin-bottom: 6px;
}

.playlist-item .text-link {
  font-size: 13px;
  font-weight: 500;
  flex-shrink: 0;
  margin-left: auto;
  align-self: center;
}

/* 相关入口 */
.related-links {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 48px;
}

.related-card {
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 24px 20px;
}

.related-card h2 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
}

.related-card p {
  font-size: 13px;
  color: var(--ink-mid);
  margin-bottom: 12px;
}

.btn-link {
  display: inline-block;
  padding: 8px 16px;
  font-size: 13px;
  font-weight: 600;
  border: 1px solid var(--accent-blue);
  color: var(--accent-blue-dark);
  border-radius: var(--radius);
  background-color: #FFFFFF;
}

.btn-link:hover {
  background-color: var(--accent-blue);
  color: #FFFFFF;
}

/* ============================================================
   Pages — 观看指南 tx/guide.html
   ============================================================ */
.guide-section {
  margin-bottom: 40px;
}

.guide-section h2 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 12px;
}

.guide-section > p {
  font-size: 15px;
  color: var(--ink-mid);
  margin-bottom: 20px;
  max-width: 700px;
}

.checklist {
  counter-reset: step-counter;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.checklist-item {
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 20px 24px;
  position: relative;
}

.checklist-head {
  font-size: 16px;
  font-weight: 600;
  color: var(--ink-strong);
  margin-bottom: 8px;
  padding-left: 36px;
  position: relative;
  line-height: 1.5;
}

.checklist-head::before {
  counter-increment: step-counter;
  content: counter(step-counter, decimal-leading-zero);
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--accent-green-dark);
  position: absolute;
  left: 0;
  top: 1px;
  font-weight: 600;
}

.checklist-item > p {
  font-size: 14px;
  color: var(--ink-body);
  margin-bottom: 8px;
  padding-left: 36px;
}

.expect-line {
  font-size: 13px;
  color: var(--ink-mid);
  border-left: 3px solid var(--accent-green);
  padding-left: 12px;
  margin: 8px 0;
}

.exception-line {
  font-size: 13px;
  color: var(--ink-mid);
  border-left: 3px solid var(--accent-blue);
  padding-left: 12px;
  margin: 8px 0;
}

/* 指南侧栏 */
.guide-aside {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.aside-card {
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 20px;
}

.aside-card h2 {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--ink-strong);
}

.aside-card p {
  font-size: 13px;
  color: var(--ink-mid);
  margin-bottom: 10px;
  line-height: 1.7;
}

.aside-card p a {
  font-weight: 500;
}

.aside-card.aside-note {
  background-color: var(--bg-soft);
  border-style: dashed;
}

.aside-note strong {
  display: block;
  font-size: 13px;
  color: var(--ink-strong);
  margin-bottom: 6px;
}

/* ============================================================
   Pages — 视频名词 tx/glossary.html
   ============================================================ */
.glossary-index {
  margin-bottom: 40px;
}

.glossary-index .section-title {
  font-size: 22px;
}

.glossary-tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 16px;
}

.glossary-tag-list li a {
  display: inline-block;
  padding: 6px 16px;
  font-size: 14px;
  font-weight: 500;
  border: 1px solid var(--line);
  border-radius: 20px;
  background-color: #FFFFFF;
  color: var(--ink-mid);
}

.glossary-tag-list li a:hover {
  border-color: var(--accent-blue);
  color: var(--accent-blue-dark);
}

.glossary-group {
  margin-bottom: 40px;
  scroll-margin-top: 80px;
}

.group-heading {
  border-left: 3px solid var(--accent-blue);
  padding-left: 16px;
  margin-bottom: 20px;
}

.group-heading .section-title {
  font-size: 20px;
  margin-bottom: 4px;
}

.group-desc {
  font-size: 13px;
  color: var(--ink-note);
}

.term-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.term-item {
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 20px;
}

.term-name {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--ink-strong);
}

.term-def {
  font-size: 14px;
  color: var(--ink-mid);
  margin-bottom: 10px;
  line-height: 1.7;
}

.term-ref {
  font-size: 12px;
  color: var(--ink-note);
  border-top: 1px dashed var(--line);
  padding-top: 8px;
}

.term-ref a {
  margin-right: 10px;
}

/* 交叉引用 */
.glossary-crossref {
  margin-top: 40px;
  padding: 24px;
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
}

.glossary-crossref .section-title {
  font-size: 20px;
}

.crossref-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  margin: 14px 0 20px;
}

.crossref-list li {
  font-size: 13px;
  color: var(--ink-mid);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 2px 10px;
  background-color: var(--bg-soft);
}

.term-key {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent-blue);
  margin-right: 4px;
}

.glossary-media {
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--line);
  margin-top: 16px;
}

.glossary-media img {
  width: 100%;
  aspect-ratio: 16 / 6;
  object-fit: cover;
}

.glossary-media figcaption {
  font-size: 12px;
  color: var(--ink-note);
  padding: 8px 12px;
  background-color: var(--bg-soft);
}

.inline-nav {
  margin-top: 32px;
  padding: 16px 20px;
  background-color: var(--bg-soft);
  border-radius: var(--radius);
  font-size: 14px;
}

.inline-nav p {
  color: var(--ink-mid);
}

.inline-nav a {
  font-weight: 500;
}

/* ============================================================
   Pages — 常见问题 tx/faq.html
   ============================================================ */
.faq-toc {
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 20px;
  position: sticky;
  top: calc(var(--header-h) + 20px);
}

.faq-toc h2 {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--ink-strong);
}

.faq-toc ul li {
  margin-bottom: 4px;
}

.faq-toc ul li a {
  display: block;
  padding: 6px 10px;
  font-size: 14px;
  color: var(--ink-mid);
  border-radius: 4px;
}

.faq-toc ul li a:hover {
  background-color: var(--accent-blue-soft);
  color: var(--accent-blue-dark);
}

.faq-toc .aside-note {
  font-size: 12px;
  color: var(--ink-note);
  border-top: 1px dashed var(--line);
  padding-top: 12px;
  margin-top: 12px;
}

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

.faq-group {
  margin-bottom: 36px;
  scroll-margin-top: 80px;
}

.faq-group > h2 {
  font-size: 20px;
  font-weight: 700;
  color: var(--ink-strong);
  margin-bottom: 14px;
  padding-bottom: 6px;
  border-bottom: 2px solid var(--line);
}

.faq-content .faq-item {
  margin-bottom: 10px;
}

.faq-content .faq-item summary {
  font-weight: 500;
}

.faq-boundary-note {
  background-color: var(--bg-soft);
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius-lg);
  padding: 24px;
  margin-top: 32px;
}

.faq-boundary-note h2 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 10px;
}

.faq-boundary-note p {
  font-size: 14px;
  color: var(--ink-mid);
  margin-bottom: 8px;
}

.faq-boundary-note p a {
  font-weight: 500;
}

.faq-figure {
  margin-top: 16px;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--line);
}

.faq-figure img {
  width: 100%;
  aspect-ratio: 16 / 7;
  object-fit: cover;
}

.faq-figure figcaption {
  font-size: 12px;
  color: var(--ink-note);
  padding: 8px 12px;
  background-color: #FFFFFF;
}

/* ============================================================
   Pages — 问题反馈 tx/feedback.html
   ============================================================ */
.feedback-hero-figure {
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--line);
  margin-bottom: 32px;
}

.feedback-hero-img {
  width: 100%;
  aspect-ratio: 21 / 8;
  object-fit: cover;
}

.feedback-scope h2,
.feedback-checklist h2,
.feedback-boundary h2,
.feedback-path h2 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--ink-strong);
}

.feedback-scope p,
.feedback-checklist p,
.feedback-boundary p,
.feedback-path p {
  font-size: 15px;
  color: var(--ink-mid);
  margin-bottom: 12px;
  max-width: 760px;
}

.scope-list {
  margin: 16px 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.scope-list li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 14px;
  color: var(--ink-body);
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 10px 16px;
}

.scope-list li::before {
  content: "01";
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent-blue);
  font-weight: 600;
  flex-shrink: 0;
  margin-top: 3px;
}

.scope-list li:nth-child(2)::before {
  content: "02";
}

.scope-list li:nth-child(3)::before {
  content: "03";
}

.scope-list li:nth-child(4)::before {
  content: "04";
}

.scope-list li:nth-child(5)::before {
  content: "05";
}

.scope-list li strong {
  color: var(--ink-strong);
  font-weight: 600;
}

.checklist-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-top: 20px;
}

.checklist-list .checklist-item {
  padding: 16px 20px;
}

.checklist-list .checklist-item h3 {
  font-size: 15px;
  font-weight: 600;
  color: var(--ink-strong);
  margin-bottom: 4px;
}

.checklist-list .checklist-item p {
  font-size: 13px;
  color: var(--ink-note);
  margin-bottom: 0;
}

.boundary-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin: 20px 0;
}

.boundary-card {
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 20px;
}

.boundary-card h3 {
  font-size: 15px;
  font-weight: 600;
  color: var(--ink-strong);
  margin-bottom: 8px;
}

.boundary-card p {
  font-size: 13px;
  color: var(--ink-mid);
  margin-bottom: 0;
}

.feedback-boundary > p > a {
  font-weight: 500;
}

.feedback-path {
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 24px;
}

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

.error-section {
  max-width: 560px;
  text-align: left;
  background-color: #FFFFFF;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 48px;
  width: 100%;
}

.error-code {
  font-size: 14px;
  color: var(--accent-blue);
  font-weight: 600;
  margin-bottom: 8px;
}

.error-section h1 {
  font-size: 30px;
  font-weight: 700;
  color: var(--ink-strong);
  margin-bottom: 12px;
}

.error-desc {
  font-size: 15px;
  color: var(--ink-mid);
  margin-bottom: 10px;
}

.error-home {
  display: inline-block;
  margin: 16px 0 24px;
  padding: 10px 20px;
  background-color: var(--accent-blue);
  color: #FFFFFF;
  font-size: 14px;
  font-weight: 600;
  border-radius: var(--radius);
}

.error-home:hover {
  background-color: var(--accent-blue-dark);
  color: #FFFFFF;
}

.error-links {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  border-top: 1px dashed var(--line);
  padding-top: 16px;
}

.error-links a {
  font-size: 14px;
  font-weight: 500;
}

/* ============================================================
   Responsive — 响应式断点
   ============================================================ */
@media (max-width: 1024px) {
  .footer-shell {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }

  .channel-card-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .advice-layout {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .channel-aside {
    width: 100%;
  }

  .layout-shell {
    grid-template-columns: minmax(0, 1fr) 260px;
    gap: 32px;
  }

  .layout-shell.sidebar-left {
    grid-template-columns: 220px minmax(0, 1fr);
  }
}

@media (max-width: 860px) {
  /* 导航切换 */
  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    background-color: #FFFFFF;
    border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow-md);
  }

  .site-nav .nav-list {
    display: none;
    flex-direction: column;
    align-items: stretch;
    padding: 12px 16px 20px;
    gap: 2px;
    max-height: calc(100vh - var(--header-h));
    overflow-y: auto;
  }

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

  .site-nav .nav-list li a {
    padding: 10px 14px;
    font-size: 15px;
  }

  /* 首页 */
  .home-hero.editorial-splash {
    grid-template-columns: 1fr;
    gap: 32px;
    padding: 32px 0;
  }

  .hero-copy h1 {
    font-size: 32px;
  }

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

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

  .topics-teaser {
    grid-template-columns: 1fr;
    gap: 24px;
  }

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

  /* 内页双栏全部改为单栏 */
  .layout-shell,
  .layout-shell.sidebar-left {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .faq-toc {
    position: static;
  }

  .faq-toc ul {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
  }

  .faq-toc ul li {
    margin-bottom: 0;
  }

  .faq-toc ul li a {
    padding: 4px 12px;
    border: 1px solid var(--line);
    border-radius: 4px;
    font-size: 13px;
  }

  /* 频道页 */
  .channel-card-grid {
    grid-template-columns: 1fr 1fr;
  }

  /* 专题页 */
  .topics-intro {
    grid-template-columns: 1fr;
    gap: 24px;
  }

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

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

  /* 名词页 */
  .term-list {
    grid-template-columns: 1fr;
  }

  /* 反馈页 */
  .boundary-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .header-shell {
    padding: 0 16px;
  }

  .site-main.inner-main {
    padding: 24px 16px 48px;
  }

  .home-main {
    padding: 0 16px;
  }

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

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

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

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

  /* 首页 */
  .hero-copy h1 {
    font-size: 27px;
  }

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

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

  .action-link {
    justify-content: center;
  }

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

  .update-strip {
    align-items: flex-start;
    flex-direction: column;
    gap: 4px;
    margin-bottom: 40px;
  }

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

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

  .channel-index-card {
    flex-wrap: wrap;
    gap: 4px 10px;
  }

  .channel-name {
    min-width: 0;
  }

  .channel-note {
    width: 100%;
  }

  /* 频道页 */
  .channel-card-grid {
    grid-template-columns: 1fr;
  }

  .channel-card h3 {
    font-size: 15px;
  }

  .table-scroll {
    border-radius: var(--radius);
  }

  .channel-table th,
  .channel-table td {
    padding: 10px 12px;
    font-size: 13px;
  }

  .advice-main {
    padding: 18px 16px;
  }

  /* 专题页 */
  .topics-intro {
    margin-bottom: 32px;
  }

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

  .playlist-item {
    flex-wrap: wrap;
    gap: 8px;
  }

  .playlist-item .text-link {
    margin-left: 0;
  }

  .playlist-info {
    width: 100%;
  }

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

  /* 指南页 */
  .checklist-item {
    padding: 16px;
  }

  .checklist-head {
    padding-left: 30px;
    font-size: 15px;
  }

  .checklist-head::before {
    font-size: 12px;
  }

  .checklist-item > p {
    padding-left: 30px;
    font-size: 13px;
  }

  .expect-line,
  .exception-line {
    margin-left: 30px;
    font-size: 13px;
  }

  /* 名词页 */
  .glossary-tag-list {
    gap: 8px;
  }

  .glossary-tag-list li a {
    padding: 4px 12px;
    font-size: 13px;
  }

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

  .glossary-crossref {
    padding: 16px;
  }

  .crossref-list {
    gap: 6px 10px;
  }

  .glossary-media img {
    aspect-ratio: 16 / 8;
  }

  /* FAQ */
  .faq-group > h2 {
    font-size: 18px;
  }

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

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

  .faq-boundary-note {
    padding: 16px;
  }

  /* 反馈页 */
  .feedback-hero-img {
    aspect-ratio: 16 / 9;
  }

  .feedback-scope h2,
  .feedback-checklist h2,
  .feedback-boundary h2,
  .feedback-path h2 {
    font-size: 18px;
  }

  .scope-list li {
    padding: 8px 12px;
    font-size: 13px;
  }

  .checklist-list .checklist-item {
    padding: 12px 14px;
  }

  .feedback-path {
    padding: 16px;
  }

  /* 404 */
  .error-section {
    padding: 32px 24px;
  }

  .error-section h1 {
    font-size: 24px;
  }
}

@media (max-width: 390px) {
  .brand-name {
    font-size: 17px;
  }

  .brand-tag {
    font-size: 10px;
  }

  .footer-shell {
    padding: 28px 16px 20px;
  }

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

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

  .hero-lead {
    font-size: 14px;
  }

  .section-heading h2,
  .section-title {
    font-size: 19px;
  }

  .guide-step {
    padding: 18px 16px;
  }

  .topic-item h3 {
    font-size: 14px;
  }

  .topic-item p {
    font-size: 12px;
  }

  .angle-item h3 {
    font-size: 15px;
  }

  .angle-item p {
    font-size: 13px;
  }

  .playlist-info h3 {
    font-size: 15px;
  }

  .playlist-info p {
    font-size: 13px;
  }

  .related-card {
    padding: 18px 16px;
  }

  .channel-aside {
    padding: 16px;
  }

  .aside-card {
    padding: 16px;
  }

  .term-name {
    font-size: 15px;
  }

  .term-def {
    font-size: 13px;
  }

  .faq-toc {
    padding: 16px;
  }

  .faq-toc ul li a {
    font-size: 12px;
  }

  .boundary-card {
    padding: 16px;
  }
}