/* ============================================================
   base — 全站基础变量、重置与排版
   ============================================================ */
:root {
  --bg: #f7f6f3;
  --surface: #ffffff;
  --ink: #26262b;
  --muted: #6f6f76;
  --accent: #b32d3a;
  --accent-soft: #f6e5e8;
  --border: #e4e1dc;
  --radius: 8px;
  --container: 1200px;
  --header-h: 64px;
  --font: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
}

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

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

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

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

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

a:hover {
  text-decoration: underline;
}

ul,
ol {
  list-style: none;
}

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

h1 {
  font-size: 30px;
}

h2 {
  font-size: 22px;
}

h3 {
  font-size: 17px;
}

p {
  color: var(--ink);
}

/* ============================================================
   layout — 页头、页脚、主容器、面包屑、页面标题区
   ============================================================ */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

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

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

.brand-name::first-letter {
  color: var(--accent);
}

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

.site-nav .nav-list a {
  display: block;
  padding: 8px 16px;
  border-radius: var(--radius);
  color: var(--ink);
  font-size: 15px;
  line-height: 1.4;
}

.site-nav .nav-list a:hover {
  background: var(--accent-soft);
  color: var(--accent);
  text-decoration: none;
}

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

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

.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--ink);
  border-radius: 2px;
}

.site-main {
  min-height: 60vh;
}

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

.breadcrumb {
  font-size: 14px;
  color: var(--muted);
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
}

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

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

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

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

.page-header {
  margin-bottom: 32px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border);
}

.page-title {
  font-size: 30px;
  margin-bottom: 8px;
}

.page-description {
  font-size: 16px;
  color: var(--muted);
  max-width: 760px;
}

.site-footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  margin-top: 48px;
}

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

.footer-col h3 {
  font-size: 15px;
  margin-bottom: 12px;
  color: var(--ink);
}

.footer-col p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
}

.footer-col a {
  display: block;
  font-size: 14px;
  color: var(--muted);
  padding: 3px 0;
}

.footer-col a:hover {
  color: var(--accent);
  text-decoration: none;
}

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

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

/* ============================================================
   components — 按钮、卡片、FAQ、表格、步骤、链接条等通用组件
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 24px;
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 600;
  line-height: 1.5;
  cursor: pointer;
  border: 1px solid transparent;
  min-height: 44px;
  transition: background 0.2s ease, border-color 0.2s ease;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: #9a2530;
  text-decoration: none;
}

.btn-secondary {
  background: var(--surface);
  color: var(--ink);
  border-color: var(--border);
}

.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
  text-decoration: none;
}

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

.section-heading h2 {
  margin-bottom: 6px;
}

.section-heading p {
  color: var(--muted);
  font-size: 15px;
}

.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  margin-bottom: 12px;
}

.faq-item summary {
  padding: 14px 18px;
  font-weight: 600;
  font-size: 15px;
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

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

.faq-item summary::after {
  content: "+";
  font-size: 20px;
  font-weight: 400;
  color: var(--muted);
  flex-shrink: 0;
  transition: transform 0.2s ease;
}

.faq-item[open] summary::after {
  transform: rotate(45deg);
}

.faq-item p {
  padding: 0 18px 14px;
  font-size: 15px;
  color: var(--muted);
}

.related-links {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
}

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

.related-links-item {
  font-size: 14px;
  padding: 6px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--ink);
}

.related-links-item:hover {
  border-color: var(--accent);
  color: var(--accent);
  text-decoration: none;
}

.text-link {
  font-size: 15px;
  color: var(--accent);
  margin-right: 20px;
  display: inline-block;
  padding: 4px 0;
}

.text-link:hover {
  text-decoration: underline;
}

/* ============================================================
   pages — 首页
   ============================================================ */
.home-main {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px 56px;
}

.hero-section {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 48px;
  align-items: center;
  padding: 48px 0 40px;
}

.hero-copy h1 {
  font-size: 32px;
  line-height: 1.3;
  margin-bottom: 12px;
}

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

.hero-desc {
  font-size: 16px;
  color: var(--muted);
  margin-bottom: 24px;
  max-width: 520px;
}

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

.hero-figure {
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--surface);
}

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

.tool-panel {
  padding: 40px 0;
}

.tool-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.tool-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px 20px;
  display: flex;
  flex-direction: column;
}

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

.tool-card p {
  font-size: 14px;
  color: var(--muted);
  margin-bottom: 16px;
  flex-grow: 1;
}

.tool-card a {
  font-size: 14px;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.tool-card a::after {
  content: "→";
  transition: transform 0.2s ease;
}

.tool-card a:hover {
  text-decoration: none;
}

.tool-card a:hover::after {
  transform: translateX(4px);
}

.scene-preview {
  padding: 40px 0;
}

.scene-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.scene-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

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

.scene-card figcaption {
  padding: 16px;
}

.scene-card figcaption h3 {
  font-size: 16px;
  margin-bottom: 6px;
}

.scene-card figcaption p {
  font-size: 14px;
  color: var(--muted);
}

.scene-more {
  margin-top: 24px;
  text-align: right;
}

.scene-more a {
  font-size: 15px;
  font-weight: 600;
}

.guide-steps {
  padding: 40px 0;
}

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

.step-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px 20px;
  position: relative;
}

.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 700;
  font-size: 18px;
  margin-bottom: 12px;
  font-family: "SF Mono", Consolas, monospace;
}

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

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

.guide-more {
  margin-top: 24px;
  text-align: center;
}

.guide-more a {
  font-size: 15px;
  font-weight: 600;
}

.update-summary {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin: 40px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
}

.update-summary h2 {
  font-size: 18px;
  margin-bottom: 4px;
}

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

.update-summary a {
  font-size: 14px;
  font-weight: 600;
  flex-shrink: 0;
}

.faq-teaser {
  padding: 0 0 40px;
}

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

.faq-more {
  margin-top: 16px;
  text-align: center;
}

.faq-more a {
  font-size: 15px;
  font-weight: 600;
}

/* ============================================================
   pages — 内页通用布局
   ============================================================ */
.page-layout {
  display: grid;
  gap: 32px;
  align-items: start;
}

.sidebar-left {
  grid-template-columns: 240px 1fr;
}

.sidebar-left > aside {
  position: sticky;
  top: calc(var(--header-h) + 24px);
}

/* ============================================================
   pages — 频道索引页 ytys/channels.html
   ============================================================ */
.channel-index-aside {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}

.channel-index-aside h2 {
  font-size: 16px;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
}

.anchor-list li {
  margin-bottom: 4px;
}

.anchor-list a {
  display: block;
  padding: 8px 12px;
  border-radius: 6px;
  font-size: 14px;
  color: var(--ink);
}

.anchor-list a:hover {
  background: var(--accent-soft);
  color: var(--accent);
  text-decoration: none;
}

.channel-parameter-main {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
}

.channel-block {
  margin-bottom: 32px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--border);
}

.channel-block:last-child {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.channel-head {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.channel-head h2 {
  font-size: 19px;
}

.channel-tag {
  display: inline-block;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 13px;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 4px;
  flex-shrink: 0;
}

.channel-params {
  display: grid;
  gap: 12px;
}

.param-row {
  display: grid;
  grid-template-columns: 88px 1fr;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px dashed var(--border);
  align-items: baseline;
}

.param-row:last-child {
  border-bottom: none;
}

.param-row dt {
  font-size: 14px;
  font-weight: 600;
  color: var(--ink);
}

.param-row dd {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
}

.channel-figure {
  margin-top: 28px;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
}

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

.channel-figure figcaption {
  padding: 12px 16px;
  font-size: 14px;
  color: var(--muted);
  background: var(--surface);
}

.channel-field-note {
  margin-top: 32px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
}

.channel-field-note h2 {
  margin-bottom: 8px;
}

.channel-field-note > p {
  color: var(--muted);
  font-size: 15px;
  margin-bottom: 20px;
}

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

.field-item {
  background: var(--bg);
  border-radius: var(--radius);
  padding: 16px;
}

.field-item h3 {
  font-size: 15px;
  margin-bottom: 6px;
  color: var(--accent);
}

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

.scene-entry-link {
  margin-top: 32px;
  background: var(--accent-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
}

.scene-entry-link h2 {
  font-size: 18px;
  margin-bottom: 4px;
}

.scene-entry-link p {
  font-size: 14px;
  color: var(--muted);
}

.scene-entry-link .btn {
  margin-left: 8px;
}

/* ============================================================
   pages — 观看场景页 ytys/scenes.html
   ============================================================ */
.scene-cards {
  margin-bottom: 40px;
}

.scene-cards h2 {
  margin-bottom: 20px;
}

.scene-card-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.scene-card-media {
  overflow: hidden;
  border-radius: var(--radius) var(--radius) 0 0;
}

.scene-card-media img {
  width: 100%;
  height: 150px;
  object-fit: cover;
}

.scene-card-body {
  padding: 16px;
}

.scene-card-body h3 {
  font-size: 16px;
  margin-bottom: 4px;
}

.scene-time {
  font-size: 13px;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 8px;
}

.scene-card-body > p {
  font-size: 14px;
  color: var(--muted);
  margin-bottom: 12px;
}

.scene-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.scene-tags li {
  font-size: 12px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 2px 8px;
  color: var(--muted);
}

.scene-comparison {
  margin-bottom: 40px;
}

.scene-comparison h2 {
  margin-bottom: 6px;
}

.scene-comparison > p {
  color: var(--muted);
  font-size: 15px;
  margin-bottom: 20px;
}

.table-scroll {
  overflow-x: auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.scene-table {
  width: 100%;
  border-collapse: collapse;
  min-width: 640px;
}

.scene-table th,
.scene-table td {
  padding: 14px 16px;
  text-align: left;
  font-size: 14px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

.scene-table th {
  background: var(--bg);
  font-weight: 600;
  color: var(--ink);
  white-space: nowrap;
}

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

.scene-table td {
  color: var(--muted);
  line-height: 1.7;
}

.scene-channel-path {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  text-align: center;
}

.scene-channel-path h2 {
  margin-bottom: 8px;
}

.scene-channel-path p {
  color: var(--muted);
  font-size: 15px;
  margin-bottom: 20px;
}

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

/* ============================================================
   pages — 观看指南页 ytys/guide.html
   ============================================================ */
.guide-layout {
  grid-template-columns: 1fr 280px;
  gap: 32px;
}

.guide-layout .breadcrumb {
  margin-bottom: 20px;
}

.guide-layout .page-header {
  margin-bottom: 28px;
}

.guide-steps-section h2 {
  margin-bottom: 20px;
}

.steps-list {
  display: grid;
  gap: 16px;
}

.guide-step {
  display: grid;
  grid-template-columns: 56px 1fr;
  gap: 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  align-items: start;
}

.step-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  font-size: 18px;
  font-family: "SF Mono", Consolas, monospace;
  flex-shrink: 0;
}

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

.step-content p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
}

.devices-note {
  margin-top: 32px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}

.devices-note h2 {
  font-size: 18px;
  margin-bottom: 16px;
}

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

.devices-list li {
  font-size: 14px;
  color: var(--muted);
  padding: 12px;
  background: var(--bg);
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.checklist-aside {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  position: sticky;
  top: calc(var(--header-h) + 24px);
}

.checklist-aside h2 {
  font-size: 16px;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
}

.checklist {
  display: grid;
  gap: 16px;
}

.checklist li {
  display: grid;
  grid-template-columns: 24px 1fr;
  gap: 8px;
  align-items: start;
}

.check-label {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 20px;
  height: 20px;
  border: 1px solid var(--accent);
  border-radius: 50%;
  color: var(--accent);
  font-size: 13px;
  font-weight: 700;
  margin-top: 2px;
}

.checklist li p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.6;
}

.guide-media {
  margin-top: 32px;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
}

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

.guide-media figcaption {
  padding: 12px 16px;
  font-size: 14px;
  color: var(--muted);
  background: var(--surface);
}

/* ============================================================
   pages — 更新说明页 ytys/updates.html
   ============================================================ */
.updates-section {
  margin-bottom: 40px;
}

.update-intro {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 32px;
  align-items: center;
  margin-bottom: 32px;
}

.update-intro-copy h2 {
  margin-bottom: 8px;
}

.update-intro-copy p {
  color: var(--muted);
  font-size: 15px;
  line-height: 1.8;
}

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

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

.update-media figcaption {
  padding: 10px 14px;
  font-size: 13px;
  color: var(--muted);
  background: var(--surface);
}

.timeline-list {
  display: grid;
  gap: 16px;
}

.timeline-item {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  align-items: start;
}

.timeline-badge {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 700;
  font-size: 14px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: "SF Mono", Consolas, monospace;
}

.timeline-body h3 {
  font-size: 16px;
  margin-bottom: 6px;
}

.timeline-body p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
}

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

.collection-section > h2 {
  margin-bottom: 8px;
}

.collection-section > p {
  color: var(--muted);
  font-size: 15px;
  margin-bottom: 20px;
}

.rule-table-wrap {
  overflow-x: auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.rule-table {
  width: 100%;
  border-collapse: collapse;
  min-width: 560px;
}

.rule-table th,
.rule-table td {
  padding: 14px 16px;
  text-align: left;
  font-size: 14px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

.rule-table th {
  background: var(--bg);
  font-weight: 600;
  color: var(--ink);
  white-space: nowrap;
}

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

.rule-table td {
  color: var(--muted);
  line-height: 1.7;
}

.future-section {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
}

.future-section h2 {
  margin-bottom: 8px;
}

.future-section > p {
  color: var(--muted);
  font-size: 15px;
  margin-bottom: 16px;
}

.future-tags {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.future-tag {
  display: inline-block;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 14px;
  font-weight: 600;
  padding: 4px 14px;
  border-radius: 4px;
}

.related-entry {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin-top: 24px;
}

.related-entry h2 {
  font-size: 16px;
  margin-bottom: 8px;
}

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

.related-entry a {
  font-size: 14px;
  font-weight: 600;
  margin-right: 16px;
}

/* ============================================================
   pages — 帮助反馈页 ytys/help.html
   ============================================================ */
.faq-toc {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}

.faq-toc h2 {
  font-size: 16px;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
}

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

.toc-list a {
  display: block;
  padding: 8px 12px;
  border-radius: 6px;
  font-size: 14px;
  color: var(--ink);
}

.toc-list a:hover {
  background: var(--accent-soft);
  color: var(--accent);
  text-decoration: none;
}

.toc-note {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}

.toc-note p {
  font-size: 13px;
  color: var(--muted);
  line-height: 1.6;
}

.faq-content {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
}

.faq-group {
  margin-bottom: 28px;
}

.faq-group h2 {
  font-size: 18px;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
}

.faq-group .faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  margin-bottom: 10px;
}

.faq-group .faq-item summary {
  padding: 14px 16px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

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

.faq-group .faq-item summary::after {
  content: "+";
  font-size: 18px;
  color: var(--muted);
  flex-shrink: 0;
}

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

.faq-group .faq-item p {
  padding: 0 16px 14px;
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
}

.feedback-process {
  margin-top: 32px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
}

.feedback-process h2 {
  margin-bottom: 20px;
}

.process-steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-bottom: 24px;
}

.process-step {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}

.process-step .step-number {
  width: 36px;
  height: 36px;
  font-size: 16px;
  margin-bottom: 10px;
  background: var(--accent-soft);
  color: var(--accent);
}

.process-step h3 {
  font-size: 15px;
  margin-bottom: 6px;
}

.process-step p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.6;
}

.feedback-figure {
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
}

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

.feedback-figure figcaption {
  padding: 10px 14px;
  font-size: 13px;
  color: var(--muted);
  background: var(--surface);
}

.form-validation-note {
  margin-top: 32px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
}

.form-validation-note h2 {
  margin-bottom: 8px;
}

.form-validation-note > p {
  color: var(--muted);
  font-size: 15px;
  margin-bottom: 16px;
}

.validation-list {
  display: grid;
  gap: 12px;
  margin-bottom: 16px;
}

.validation-list li {
  font-size: 14px;
  color: var(--muted);
  padding: 12px 16px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  line-height: 1.6;
}

.validation-list strong {
  color: var(--ink);
  font-weight: 600;
  margin-right: 6px;
}

.validation-tip {
  font-size: 14px;
  color: var(--muted);
  border-left: 3px solid var(--accent);
  padding-left: 14px;
  line-height: 1.7;
}

/* ============================================================
   pages — 404 页
   ============================================================ */
.error-main {
  max-width: var(--container);
  margin: 0 auto;
  padding: 64px 24px;
}

.error-panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 48px 32px;
  text-align: center;
  max-width: 640px;
  margin: 0 auto;
}

.error-code {
  font-size: 64px;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 16px;
  font-family: "SF Mono", Consolas, monospace;
}

.error-panel h1 {
  font-size: 24px;
  margin-bottom: 12px;
}

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

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

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

.error-help a {
  margin: 0 8px;
  font-weight: 600;
}

/* ============================================================
   responsive — 响应式断点
   ============================================================ */
@media (max-width: 1024px) {
  .tool-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

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

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

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

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

@media (max-width: 768px) {
  .header-inner {
    padding: 0 16px;
    height: 56px;
  }

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

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: absolute;
    top: 56px;
    left: 0;
    right: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
  }

  .site-nav .nav-list {
    display: none;
    flex-direction: column;
    align-items: stretch;
    padding: 8px 16px 16px;
    gap: 2px;
  }

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

  .site-nav .nav-list a {
    padding: 12px 16px;
    font-size: 16px;
    border-radius: 6px;
  }

  .site-nav .nav-list a.is-current {
    background: var(--accent-soft);
    color: var(--accent);
  }

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

  .home-main {
    padding: 0 16px 48px;
  }

  .hero-section {
    grid-template-columns: 1fr;
    gap: 24px;
    padding: 32px 0 24px;
  }

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

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

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

  .update-summary {
    flex-direction: column;
    align-items: flex-start;
  }

  .page-layout.sidebar-left,
  .guide-layout {
    grid-template-columns: 1fr;
  }

  .sidebar-left > aside,
  .checklist-aside {
    position: static;
    order: 2;
  }

  .sidebar-left > div,
  .guide-layout .main-content {
    order: 1;
  }

  .channel-parameter-main,
  .faq-content {
    padding: 20px;
  }

  .param-row {
    grid-template-columns: 72px 1fr;
  }

  .update-intro {
    grid-template-columns: 1fr;
    gap: 16px;
  }

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

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

@media (max-width: 480px) {
  .tool-grid {
    grid-template-columns: 1fr;
  }

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

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

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

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

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

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

  .guide-step {
    grid-template-columns: 48px 1fr;
    padding: 16px;
  }

  .timeline-item {
    grid-template-columns: 40px 1fr;
    padding: 16px;
  }

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

  .hero-actions .btn {
    text-align: center;
  }

  .path-actions {
    flex-direction: column;
  }

  .path-actions .btn {
    text-align: center;
  }

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

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

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

  .scene-entry-link {
    flex-direction: column;
    align-items: flex-start;
  }

  .scene-entry-link .btn {
    margin-left: 0;
  }

  .param-row {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .param-row dt {
    font-size: 13px;
  }

  .param-row dd {
    font-size: 14px;
  }
}