/* ==========================================================================
   base — 全站基础
   ========================================================================== */

:root {
  --color-white: #ffffff;
  --color-ink: #222222;
  --color-muted: #666666;
  --color-faint: #999999;
  --color-line: #eeeeee;
  --color-urban: #2a9d8f;
  --color-costume: #e76f51;
  --color-suspense: #457b9d;
  --color-family: #f4a261;
  --color-accent: #2a9d8f;
  --font-stack: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --container-width: 1200px;
  --radius: 8px;
  --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.06);
}

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

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

body {
  font-family: var(--font-stack);
  font-size: 15px;
  line-height: 1.7;
  color: var(--color-ink);
  background: var(--color-white);
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: #1f7a70;
}

ul,
ol {
  list-style: none;
}

h1,
h2,
h3 {
  font-weight: 700;
  line-height: 1.35;
  color: var(--color-ink);
}

h1 {
  font-size: 28px;
}

h2 {
  font-size: 21px;
}

h3 {
  font-size: 16px;
}

p {
  margin-bottom: 1rem;
}

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

/* ==========================================================================
   layout — 全站骨架
   ========================================================================== */

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

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

.header-inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 20px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  position: relative;
}

.brand-name {
  margin: 0;
  flex-shrink: 0;
}

.brand-name a {
  font-size: 20px;
  font-weight: 700;
  color: var(--color-ink);
  letter-spacing: 0.01em;
}

.brand-name a:hover {
  color: var(--color-accent);
}

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

.site-footer {
  background: #fafafa;
  border-top: 1px solid var(--color-line);
  margin-top: 64px;
}

.footer-inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 40px 20px 24px;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 32px;
}

.footer-brand p {
  font-size: 13px;
  color: var(--color-muted);
  line-height: 1.6;
  margin-bottom: 8px;
}

.footer-logo {
  font-size: 18px;
  font-weight: 700;
  color: var(--color-ink);
  margin-bottom: 8px;
}

.footer-links h2 {
  font-size: 14px;
  margin-bottom: 12px;
  color: var(--color-ink);
}

.footer-links ul li {
  margin-bottom: 6px;
}

.footer-links ul li a {
  font-size: 13px;
  color: var(--color-muted);
}

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

.copyright {
  grid-column: 1 / -1;
  border-top: 1px solid var(--color-line);
  padding-top: 16px;
  margin-top: 16px;
  font-size: 12px;
  color: var(--color-faint);
  text-align: left;
}

/* 内页布局容器 */

.page-layout,
.layout-shell {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 24px 20px 0;
  width: 100%;
}

/* 侧栏在左的布局：侧栏在前，主内容在后 */

.sidebar-left {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 40px;
  align-items: start;
}

.sidebar-left .tree-nav {
  grid-column: 1;
  grid-row: 1;
}

.sidebar-left .site-main {
  grid-column: 2;
  grid-row: 1;
  min-width: 0;
}

/* 无侧栏的内页主容器 */

.inner-main {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 24px 20px 0;
  width: 100%;
}

/* 面包屑 */

.breadcrumb {
  font-size: 13px;
  color: var(--color-muted);
  padding: 12px 0 16px;
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}

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

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

.breadcrumb-sep {
  color: #ccc;
}

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

/* 页面标题区 */

.page-header {
  padding: 8px 0 20px;
  margin-bottom: 8px;
}

.page-title {
  font-size: 26px;
  margin-bottom: 10px;
}

.page-description {
  font-size: 15px;
  color: var(--color-muted);
  max-width: 720px;
  margin-bottom: 0;
}

/* ==========================================================================
   导航
   ========================================================================== */

.nav-toggle {
  display: none;
  background: none;
  border: 0;
  cursor: pointer;
  padding: 10px;
  flex-direction: column;
  gap: 4px;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
}

.toggle-bar {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-ink);
  border-radius: 1px;
  transition: background 0.2s ease;
}

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

.nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
  margin: 0;
  padding: 0;
}

.nav-list li a {
  display: block;
  padding: 8px 14px;
  font-size: 14px;
  color: var(--color-ink);
  border-radius: 4px;
  transition: background 0.2s ease, color 0.2s ease;
}

.nav-list li a:hover {
  background: #f2f7f6;
  color: var(--color-accent);
}

.nav-list li a.is-current {
  color: var(--color-accent);
  font-weight: 600;
  background: #edf5f4;
}

/* ==========================================================================
   侧栏树状导航
   ========================================================================== */

.tree-nav {
  background: #fafafa;
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  padding: 20px 16px;
  position: sticky;
  top: 88px;
  font-size: 14px;
}

.tree-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--color-ink);
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--color-line);
}

.tree-section h2 {
  font-size: 13px;
  font-weight: 600;
  color: var(--color-muted);
  margin-bottom: 10px;
  text-transform: none;
}

.tree-list {
  margin-bottom: 16px;
}

.tree-list li {
  margin-bottom: 2px;
}

.tree-list li a {
  display: block;
  padding: 7px 10px;
  font-size: 13px;
  color: var(--color-muted);
  border-left: 3px solid transparent;
  transition: all 0.2s ease;
}

.tree-list li a:hover {
  color: var(--color-accent);
  border-left-color: var(--color-accent);
  background: #f0f7f6;
}

.tree-list li.is-active a {
  color: var(--color-accent);
  font-weight: 600;
  border-left-color: var(--color-accent);
  background: #f0f7f6;
}

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

/* 区块标题 */

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

.section-heading h1,
.section-heading h2 {
  margin-bottom: 8px;
}

.section-heading p {
  color: var(--color-muted);
  font-size: 14px;
  max-width: 720px;
  margin-bottom: 0;
}

.section-intro {
  color: var(--color-muted);
  font-size: 14px;
  max-width: 720px;
  margin-bottom: 20px;
}

/* 文字链接 */

.text-link {
  font-size: 14px;
  font-weight: 600;
  display: inline-block;
}

.text-link::after {
  content: " →";
  transition: margin-left 0.2s ease;
}

.text-link:hover::after {
  margin-left: 4px;
}

/* 频道色条 */

.channel-card {
  border-left: 4px solid var(--color-line);
}

.channel-urban {
  border-left-color: var(--color-urban);
}

.channel-costume {
  border-left-color: var(--color-costume);
}

.channel-suspense {
  border-left-color: var(--color-suspense);
}

.channel-family {
  border-left-color: var(--color-family);
}

/* 卡片通用 */

.step-card,
.channel-card,
.guide-card,
.method-card,
.example-item,
.guide-link-card,
.start-card,
.check-card,
.overlap-item,
.judge-item {
  background: var(--color-white);
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  padding: 20px;
}

/* ==========================================================================
   components — 首页
   ========================================================================== */

.home-main {
  overflow: visible;
}

/* 步骤导向首屏 */

.steps-section {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 40px 20px 16px;
}

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

.step-card {
  position: relative;
  padding: 28px 20px 22px;
  box-shadow: var(--shadow-card);
}

.step-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--color-accent);
  color: var(--color-white);
  font-size: 15px;
  font-weight: 700;
  margin-bottom: 14px;
}

.step-card h2 {
  font-size: 17px;
  margin-bottom: 8px;
}

.step-card p {
  font-size: 14px;
  color: var(--color-muted);
  margin-bottom: 14px;
}

.step-card a {
  font-size: 13px;
  font-weight: 600;
}

/* 频道导航带 */

.channel-strip {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 32px 20px;
}

.channel-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.channel-card {
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.channel-card h3 {
  font-size: 16px;
  margin-bottom: 8px;
}

.channel-card p {
  font-size: 13px;
  color: var(--color-muted);
  margin-bottom: 12px;
}

.channel-card a {
  font-size: 13px;
  font-weight: 600;
}

/* 片单参考区 */

.collection-preview {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 32px 20px;
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 32px;
  align-items: start;
}

.collection-info h2 {
  margin-bottom: 12px;
}

.collection-info p {
  font-size: 14px;
  color: var(--color-muted);
}

.collection-example {
  background: #fafafa;
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  padding: 20px;
}

.collection-example h3 {
  font-size: 15px;
  margin-bottom: 14px;
}

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

.example-list li {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  background: var(--color-white);
  border: 1px solid var(--color-line);
  border-radius: 4px;
  font-size: 13px;
  color: var(--color-ink);
}

.example-tag {
  display: inline-block;
  padding: 2px 8px;
  background: #edf5f4;
  color: var(--color-accent);
  border-radius: 3px;
  font-size: 12px;
  font-weight: 600;
  white-space: nowrap;
}

/* 观看指南入口卡 */

.guide-cards {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 16px 20px 40px;
}

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

.guide-card {
  box-shadow: var(--shadow-card);
}

.guide-card h3 {
  font-size: 15px;
  margin-bottom: 6px;
}

.guide-card p {
  font-size: 13px;
  color: var(--color-muted);
  margin-bottom: 10px;
}

.guide-card a {
  font-size: 13px;
  font-weight: 600;
}

/* 媒体展示区 */

.media-showcase {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 20px 40px;
}

.hero-figure {
  margin-bottom: 16px;
}

.hero-figure img {
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 1.2;
  object-fit: cover;
  border-radius: var(--radius);
}

.hero-figure figcaption {
  font-size: 13px;
  color: var(--color-muted);
  padding-top: 8px;
}

.sub-figures {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

.sub-figures figure {
  margin: 0;
}

.sub-figures img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-radius: var(--radius);
}

.sub-figures figcaption {
  font-size: 12px;
  color: var(--color-muted);
  padding-top: 6px;
}

/* ==========================================================================
   components — 频道速查页
   ========================================================================== */

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

.category-list h2 {
  margin-bottom: 8px;
}

.category-list > p {
  color: var(--color-muted);
  font-size: 14px;
  margin-bottom: 20px;
}

.table-wrapper {
  overflow-x: auto;
  margin-bottom: 20px;
}

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

.category-table th,
.category-table td {
  text-align: left;
  padding: 12px 14px;
  border-bottom: 1px solid var(--color-line);
  vertical-align: top;
}

.category-table thead th {
  background: #fafafa;
  font-weight: 600;
  border-bottom: 2px solid var(--color-line);
  white-space: nowrap;
}

.category-table tbody tr:hover {
  background: #fafafa;
}

.category-figure {
  margin: 20px 0 0;
}

.category-figure img {
  width: 100%;
  aspect-ratio: 16 / 6;
  object-fit: cover;
  border-radius: var(--radius);
}

.category-figure figcaption {
  font-size: 12px;
  color: var(--color-muted);
  padding-top: 6px;
}

/* 判断提示 */

.note {
  margin-bottom: 40px;
}

.note h2 {
  margin-bottom: 12px;
}

.note > p {
  color: var(--color-muted);
  font-size: 14px;
  margin-bottom: 16px;
}

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

.judge-item h3 {
  font-size: 15px;
  margin-bottom: 6px;
}

.judge-item p {
  font-size: 13px;
  color: var(--color-muted);
  margin-bottom: 0;
}

/* 相邻频道区分 */

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

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

.overlap-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-bottom: 16px;
}

.overlap-item h3 {
  font-size: 15px;
  margin-bottom: 8px;
}

.overlap-item p {
  font-size: 13px;
  color: var(--color-muted);
  margin-bottom: 0;
}

.overlap-note > p {
  font-size: 14px;
  color: var(--color-muted);
}

/* 内页相关推荐 */

.inner-links {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin: 32px 0 8px;
}

.guide-link-card h2 {
  font-size: 16px;
  margin-bottom: 6px;
}

.guide-link-card p {
  font-size: 13px;
  color: var(--color-muted);
  margin-bottom: 10px;
}

/* ==========================================================================
   components — 片单参考页
   ========================================================================== */

.method-section,
.examples-section,
.usage-guide {
  margin-bottom: 40px;
}

.method-section h2,
.examples-section h2,
.usage-guide h2 {
  margin-bottom: 8px;
}

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

.method-card h3 {
  font-size: 15px;
  margin-bottom: 8px;
}

.method-card p {
  font-size: 13px;
  color: var(--color-muted);
  margin-bottom: 12px;
}

.method-list {
  padding: 0;
}

.method-list li {
  font-size: 13px;
  color: var(--color-muted);
  padding: 6px 0 6px 16px;
  position: relative;
}

.method-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 13px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-accent);
}

.example-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.example-item {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 16px;
  align-items: start;
}

.example-media img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border-radius: 4px;
}

.example-content h3 {
  font-size: 15px;
  margin-bottom: 6px;
}

.example-content p {
  font-size: 13px;
  color: var(--color-muted);
  margin-bottom: 8px;
}

.example-content ul {
  display: flex;
  gap: 8px;
  margin-bottom: 8px;
}

.example-content ul li {
  font-size: 12px;
  color: var(--color-accent);
  background: #edf5f4;
  padding: 2px 8px;
  border-radius: 3px;
}

.tip-text {
  font-size: 12px;
  color: var(--color-faint);
  border-left: 3px solid var(--color-line);
  padding-left: 10px;
  margin-bottom: 0;
}

/* 使用引导 */

.usage-content {
  background: #fafafa;
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  padding: 20px;
}

.usage-content p {
  font-size: 14px;
  color: var(--color-muted);
  margin-bottom: 16px;
}

.usage-actions {
  display: flex;
  gap: 16px;
}

/* ==========================================================================
   components — 观看指南页
   ========================================================================== */

.guide-media {
  margin-bottom: 28px;
}

.guide-media img {
  width: 100%;
  aspect-ratio: 16 / 5;
  object-fit: cover;
  border-radius: var(--radius);
}

.guide-media figcaption {
  font-size: 12px;
  color: var(--color-muted);
  padding-top: 6px;
}

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

.step-list h2 {
  margin-bottom: 8px;
}

.step-item {
  position: relative;
  padding: 24px 20px 20px 76px;
  border-left: 1px solid var(--color-line);
  margin-left: 16px;
  margin-bottom: 8px;
}

.step-item .step-number {
  position: absolute;
  left: -16px;
  top: 24px;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--color-accent);
  color: var(--color-white);
  font-size: 14px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

.step-item h3 {
  font-size: 16px;
  margin-bottom: 6px;
}

.step-item p {
  font-size: 14px;
  color: var(--color-muted);
  margin-bottom: 8px;
}

.step-tip {
  font-size: 13px;
  color: var(--color-accent);
  background: #f0f7f6;
  border-radius: 4px;
  padding: 8px 12px;
  display: inline-block;
  margin-bottom: 8px;
}

.step-item a {
  font-size: 13px;
  font-weight: 600;
}

/* 核验清单 */

.checklist {
  margin-bottom: 40px;
}

.checklist h2 {
  margin-bottom: 8px;
}

.check-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

.check-card {
  padding: 16px;
}

.check-card h3 {
  font-size: 14px;
  margin-bottom: 6px;
}

.check-card p {
  font-size: 13px;
  color: var(--color-muted);
  margin-bottom: 0;
}

/* 新手起步 */

.quick-start {
  margin-bottom: 40px;
}

.quick-start h2 {
  margin-bottom: 8px;
}

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

.start-card h3 {
  font-size: 15px;
  margin-bottom: 6px;
}

.start-card p {
  font-size: 13px;
  color: var(--color-muted);
  margin-bottom: 0;
}

/* 相关链接 */

.related-links {
  margin-bottom: 40px;
}

.related-links h2 {
  font-size: 17px;
  margin-bottom: 12px;
}

.related-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.related-list li a {
  font-size: 14px;
  color: var(--color-accent);
}

.related-list li a:hover {
  text-decoration: underline;
}

/* ==========================================================================
   components — 常见问题页
   ========================================================================== */

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

.answer-group h2 {
  margin-bottom: 16px;
}

.content-media-inline {
  margin: 16px 0 20px;
}

.content-media-inline img {
  width: 100%;
  aspect-ratio: 16 / 5;
  object-fit: cover;
  border-radius: var(--radius);
}

.content-media-inline figcaption {
  font-size: 12px;
  color: var(--color-muted);
  padding-top: 6px;
}

.faq-item {
  border: 1px solid var(--color-line);
  border-radius: 6px;
  margin-bottom: 10px;
  background: var(--color-white);
  overflow: hidden;
}

.faq-item summary {
  cursor: pointer;
  padding: 14px 20px;
  font-size: 14px;
  font-weight: 600;
  color: var(--color-ink);
  list-style: none;
  position: relative;
  padding-right: 40px;
  transition: background 0.2s ease;
}

.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-muted);
  transition: transform 0.2s ease;
}

.faq-item[open] summary {
  background: #fafafa;
}

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

.faq-item summary:hover {
  background: #fafafa;
}

.faq-answer {
  padding: 0 20px 16px;
  border-top: 1px solid var(--color-line);
}

.faq-answer p {
  font-size: 14px;
  color: var(--color-muted);
  padding-top: 14px;
  margin-bottom: 0;
  line-height: 1.7;
}

.faq-answer a {
  font-size: 14px;
  font-weight: 600;
  word-break: break-word;
}

/* 问题归属表 */

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

.faq-nav h2 {
  margin-bottom: 8px;
}

.faq-nav > p {
  color: var(--color-muted);
  font-size: 14px;
  margin-bottom: 16px;
}

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

.faq-table th,
.faq-table td {
  text-align: left;
  padding: 12px 14px;
  border-bottom: 1px solid var(--color-line);
  vertical-align: top;
}

.faq-table thead th {
  background: #fafafa;
  font-weight: 600;
  border-bottom: 2px solid var(--color-line);
}

/* 未解决问题指引 */

.faq-more {
  margin-bottom: 40px;
  background: #fafafa;
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  padding: 24px;
}

.faq-more h2 {
  font-size: 17px;
  margin-bottom: 12px;
}

.faq-more p {
  font-size: 14px;
  color: var(--color-muted);
  margin-bottom: 8px;
}

.faq-more a {
  font-weight: 600;
}

/* ==========================================================================
   components — 内容边界页
   ========================================================================== */

.boundary-list,
.non-promises,
.feedback {
  margin-bottom: 40px;
}

.boundary-list h2,
.non-promises h2,
.feedback h2 {
  margin-bottom: 12px;
}

.boundary-list > p,
.non-promises > p,
.feedback > p {
  font-size: 14px;
  color: var(--color-muted);
  margin-bottom: 12px;
}

.boundary-items {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 12px;
}

.boundary-item {
  background: #fafafa;
  border-left: 4px solid var(--color-accent);
  border-radius: 4px;
  padding: 16px 20px;
}

.boundary-item h3 {
  font-size: 15px;
  margin-bottom: 6px;
}

.boundary-item p {
  font-size: 13px;
  color: var(--color-muted);
  margin-bottom: 0;
}

.non-promise-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin-top: 12px;
}

.non-promise-item {
  background: var(--color-white);
  border: 1px solid var(--color-line);
  border-radius: 6px;
  padding: 16px;
}

.non-promise-item h3 {
  font-size: 14px;
  margin-bottom: 6px;
}

.non-promise-item p {
  font-size: 13px;
  color: var(--color-muted);
  margin-bottom: 0;
}

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

.feedback b {
  font-weight: 600;
}

.feedback a {
  font-weight: 600;
}

/* ==========================================================================
   components — 404
   ========================================================================== */

.error-main {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 60px 20px;
  min-height: 60vh;
}

.error-panel {
  text-align: center;
  max-width: 520px;
  width: 100%;
}

.error-panel h1 {
  font-size: 32px;
  margin-bottom: 8px;
}

.error-code {
  font-size: 72px;
  font-weight: 700;
  color: var(--color-line);
  line-height: 1;
  margin-bottom: 8px;
}

.error-desc {
  font-size: 16px;
  color: var(--color-ink);
  margin-bottom: 8px;
}

.error-advice {
  font-size: 14px;
  color: var(--color-muted);
  margin-bottom: 24px;
}

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

.btn-back,
.btn-link {
  display: inline-block;
  padding: 10px 20px;
  font-size: 14px;
  font-weight: 600;
  border-radius: 6px;
  transition: all 0.2s ease;
}

.btn-back {
  background: var(--color-accent);
  color: var(--color-white);
}

.btn-back:hover {
  background: #1f7a70;
  color: var(--color-white);
}

.btn-link {
  background: var(--color-white);
  color: var(--color-accent);
  border: 1px solid var(--color-accent);
}

.btn-link:hover {
  background: #f0f7f6;
}

/* ==========================================================================
   responsive — 响应式
   ========================================================================== */

@media (max-width: 1080px) {
  .channel-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .judge-grid {
    grid-template-columns: repeat(3, 1fr);
  }

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

  .copyright {
    grid-column: 1 / -1;
  }

  .sidebar-left {
    grid-template-columns: 200px 1fr;
    gap: 24px;
  }
}

@media (max-width: 900px) {
  .nav-toggle {
    display: flex;
    order: 3;
  }

  .site-nav {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--color-white);
    border-bottom: 1px solid var(--color-line);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.06);
    display: block;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }

  .site-nav .nav-list {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    padding: 8px 0;
    max-height: none;
    overflow: visible;
  }

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

  .site-nav.is-open {
    max-height: calc(100vh - 64px);
    overflow-y: auto;
  }

  .nav-list li a {
    padding: 12px 20px;
    font-size: 15px;
    border-radius: 0;
  }

  .header-inner {
    flex-wrap: nowrap;
  }

  .brand-name {
    order: 1;
  }

  .nav-toggle {
    order: 2;
    margin-left: auto;
  }

  .site-nav {
    order: 3;
    width: 100%;
  }

  .header-inner {
    flex-wrap: wrap;
  }

  .site-nav {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
  }

  /* 内页布局：移动端主内容在前 */

  .sidebar-left {
    display: flex;
    flex-direction: column;
    gap: 0;
  }

  .sidebar-left .tree-nav {
    order: 2;
    position: static;
    margin-top: 24px;
    width: 100%;
  }

  .sidebar-left .site-main {
    order: 1;
    width: 100%;
  }

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

  .collection-preview {
    grid-template-columns: 1fr;
    gap: 24px;
  }

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

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

  .sub-figures {
    grid-template-columns: 1fr;
  }

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

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

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

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

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

  .example-item {
    grid-template-columns: 100px 1fr;
    gap: 12px;
  }

  .page-layout,
  .layout-shell {
    padding-top: 16px;
  }
}

@media (max-width: 640px) {
  html {
    font-size: 15px;
  }

  h1 {
    font-size: 24px;
  }

  h2 {
    font-size: 19px;
  }

  .header-inner {
    height: 56px;
    padding: 0 16px;
  }

  .site-nav {
    top: 56px;
  }

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

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

  .copyright {
    margin-top: 8px;
  }

  .steps-section,
  .channel-strip,
  .collection-preview,
  .guide-cards,
  .media-showcase {
    padding-left: 16px;
    padding-right: 16px;
  }

  .page-layout,
  .layout-shell,
  .inner-main {
    padding-left: 16px;
    padding-right: 16px;
  }

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

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

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

  .category-table th,
  .category-table td {
    padding: 10px 8px;
  }

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

  .example-media img {
    aspect-ratio: 16 / 9;
  }

  .step-item {
    padding-left: 20px;
    margin-left: 0;
    border-left: 0;
  }

  .step-item .step-number {
    position: static;
    margin-bottom: 10px;
  }

  .usage-actions {
    flex-direction: column;
    gap: 8px;
  }

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

  .tree-nav {
    padding: 16px 12px;
  }

  .tree-list li a {
    padding: 8px 8px;
  }
}

@media (max-width: 390px) {
  .nav-list li a {
    font-size: 14px;
    padding: 12px 16px;
  }

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

  .page-description {
    font-size: 14px;
  }

  .faq-item summary {
    font-size: 13px;
    padding: 12px 36px 12px 14px;
  }

  .faq-answer p {
    font-size: 13px;
  }

  .table-wrapper {
    margin: 0 -4px;
  }

  .category-table th,
  .category-table td {
    padding: 10px 6px;
    font-size: 12px;
  }

  .check-card,
  .start-card,
  .boundary-item,
  .non-promise-item {
    padding: 14px;
  }
}