/* ============================================================
   base / reset & 全局基础
   ============================================================ */
*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: #3F3A36;
  background-color: #FBF7F2;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.2s ease, background-color 0.2s ease, border-color 0.2s ease;
}

a:hover {
  color: #B2232D;
}

a:focus-visible {
  outline: 2px solid #B2232D;
  outline-offset: 2px;
  border-radius: 4px;
}

button {
  font-family: inherit;
  font-size: inherit;
  line-height: inherit;
  color: inherit;
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
}

ul,
ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

h1,
h2,
h3,
h4,
p,
figure {
  margin: 0;
}

h1,
h2,
h3,
h4 {
  font-weight: 700;
  color: #332A28;
  line-height: 1.3;
}

h1 {
  font-size: 32px;
}

h2 {
  font-size: 24px;
}

h3 {
  font-size: 18px;
}

p {
  color: #3F3A36;
}

small {
  font-size: 0.875em;
}

/* 全局容器宽度 */
.header-inner,
.footer-grid,
.footer-bottom,
.hero-map,
.channel-strip,
.public-index,
.viewing-setup,
.content-timeline,
.guide-entry,
.page-header,
.breadcrumb,
.inner-container,
.layout-shell,
.related-links,
.usage-lead,
.usage-timeline,
.usage-scenarios,
.usage-resources,
.usage-further,
.boundary-intro-section,
.boundary-rules-section,
.citation-rules-section,
.boundary-image-section,
.feedback-path-section,
.error-panel {
  width: 100%;
  max-width: 1180px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

/* ============================================================
   layout / 全站统一页头
   ============================================================ */
.site-header {
  background-color: #FFFFFF;
  border-bottom: 1px solid #E6DDD5;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 68px;
  gap: 24px;
}

.brand-link {
  display: inline-flex;
  align-items: center;
  flex-shrink: 0;
  font-weight: 700;
  font-size: 20px;
  color: #B2232D;
  letter-spacing: 0.5px;
}

.brand-link:hover {
  color: #8F1A22;
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  border: 1px solid #E6DDD5;
  border-radius: 6px;
  background-color: #FFFFFF;
}

.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  background-color: #332A28;
  border-radius: 1px;
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.site-nav {
  display: block;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 6px;
}

.nav-list li {
  position: relative;
}

.nav-list a {
  display: block;
  padding: 10px 16px;
  font-size: 15px;
  font-weight: 500;
  color: #3F3A36;
  border-radius: 6px;
  white-space: nowrap;
}

.nav-list a:hover {
  color: #B2232D;
  background-color: #FBF7F2;
}

.nav-list a.is-current {
  color: #B2232D;
  font-weight: 700;
  background-color: rgba(178, 35, 45, 0.06);
}

/* ============================================================
   layout / 全站统一页脚
   ============================================================ */
.site-footer {
  background-color: #332A28;
  margin-top: 80px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1.2fr 1fr;
  gap: 40px;
  padding-top: 56px;
  padding-bottom: 48px;
}

.footer-col h3 {
  color: #F5EDE4;
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 14px;
}

.footer-col p,
.footer-col li a {
  color: #BDB3AC;
  font-size: 14px;
  line-height: 1.8;
}

.footer-brand-link {
  display: inline-block;
  color: #E8A23C;
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 10px;
}

.footer-brand-link:hover {
  color: #F0B85A;
}

.footer-nav li a {
  display: inline-block;
  padding: 3px 0;
}

.footer-nav li a:hover {
  color: #FFFFFF;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  padding-top: 18px;
  padding-bottom: 22px;
}

.footer-bottom p {
  color: #8E837C;
  font-size: 13px;
  text-align: center;
}

/* ============================================================
   layout / 内页统一骨架
   ============================================================ */
.site-main {
  min-height: 60vh;
}

.site-main.inner-main {
  padding-top: 36px;
  padding-bottom: 16px;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: #8E837C;
  margin-bottom: 24px;
}

.breadcrumb a {
  color: #B2232D;
}

.breadcrumb a:hover {
  text-decoration: underline;
}

.breadcrumb-sep {
  color: #C4BAB2;
  user-select: none;
}

.breadcrumb-current {
  color: #3F3A36;
  font-weight: 500;
}

.page-header {
  margin-bottom: 36px;
}

.page-title {
  font-size: 32px;
  color: #332A28;
  margin-bottom: 10px;
}

.page-description {
  font-size: 15px;
  color: #6B615B;
  max-width: 720px;
  line-height: 1.8;
}

.archive-no {
  display: inline-block;
  font-family: "SF Mono", "Cascadia Code", Consolas, "Courier New", monospace;
  font-size: 13px;
  font-weight: 500;
  color: #B2232D;
  background-color: rgba(178, 35, 45, 0.08);
  border: 1px solid rgba(178, 35, 45, 0.2);
  border-radius: 4px;
  padding: 3px 10px;
  margin-bottom: 14px;
  font-variant-numeric: tabular-nums;
}

/* ============================================================
   layout / 首页频道地图首屏
   ============================================================ */
.hero-map {
  padding-top: 48px;
  padding-bottom: 56px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  gap: 48px;
}

.hero-copy h1 {
  font-size: 40px;
  line-height: 1.25;
  margin-bottom: 18px;
}

.hero-lead {
  font-size: 17px;
  line-height: 1.8;
  color: #5C534E;
  margin-bottom: 28px;
  max-width: 480px;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background-color: #B2232D;
  color: #FFFFFF;
  font-size: 15px;
  font-weight: 600;
  padding: 12px 28px;
  border-radius: 6px;
  border: 1px solid #B2232D;
  transition: background-color 0.2s ease, border-color 0.2s ease;
}

.btn-primary:hover {
  background-color: #8F1A22;
  border-color: #8F1A22;
  color: #FFFFFF;
}

.hero-figure {
  position: relative;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid #E6DDD5;
  background-color: #FFFFFF;
}

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

.hero-figure figcaption {
  background-color: #FFFFFF;
  padding: 12px 16px;
  font-size: 13px;
  color: #6B615B;
  border-top: 1px solid #F0EAE3;
}

/* ============================================================
   layout / 首页频道导航卡带
   ============================================================ */
.section-block {
  padding-top: 56px;
  padding-bottom: 56px;
}

.channel-strip {
  border-top: 1px solid #E6DDD5;
}

.channel-strip h2,
.public-index h2,
.viewing-setup h2,
.content-timeline h2,
.guide-entry h2 {
  font-size: 26px;
  margin-bottom: 12px;
}

.channel-strip > p,
.public-index > p,
.viewing-setup > p,
.content-timeline > p,
.guide-entry > p {
  color: #6B615B;
  margin-bottom: 32px;
  max-width: 640px;
}

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

.channel-card {
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  padding: 24px 20px;
  display: flex;
  flex-direction: column;
  transition: box-shadow 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

.channel-card:hover {
  box-shadow: 0 4px 16px rgba(51, 42, 40, 0.06);
  border-color: #D8C8BE;
  transform: translateY(-2px);
}

.channel-no {
  display: inline-block;
  font-family: "SF Mono", "Cascadia Code", Consolas, "Courier New", monospace;
  font-size: 12px;
  font-weight: 600;
  color: #B2232D;
  background-color: rgba(178, 35, 45, 0.07);
  border-radius: 4px;
  padding: 2px 8px;
  margin-bottom: 12px;
  align-self: flex-start;
  font-variant-numeric: tabular-nums;
}

.channel-card h3 {
  font-size: 18px;
  margin-bottom: 8px;
}

.channel-card p {
  font-size: 14px;
  color: #6B615B;
  line-height: 1.7;
  flex-grow: 1;
}

.channel-card > a {
  display: inline-block;
  margin-top: 16px;
  font-size: 14px;
  font-weight: 600;
  color: #B2232D;
}

.channel-card > a:hover {
  text-decoration: underline;
}

/* ============================================================
   layout / 公开资料目录
   ============================================================ */
.public-index {
  border-top: 1px solid #E6DDD5;
  background-color: #FFFFFF;
  border-left: none;
  border-right: none;
}

.public-index .section-block {
  max-width: 1180px;
  margin: 0 auto;
  padding-left: 24px;
  padding-right: 24px;
}

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

.index-card {
  background-color: #FBF7F2;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  padding: 24px 20px;
  transition: background-color 0.2s ease, border-color 0.2s ease;
}

.index-card:hover {
  background-color: #FFFFFF;
  border-color: #B2232D;
}

.index-card .index-no {
  display: block;
  font-family: "SF Mono", "Cascadia Code", Consolas, "Courier New", monospace;
  font-size: 12px;
  color: #B2232D;
  font-weight: 600;
  margin-bottom: 10px;
  font-variant-numeric: tabular-nums;
}

.index-card h3 {
  font-size: 17px;
  margin-bottom: 6px;
}

.index-card p {
  font-size: 13px;
  color: #6B615B;
  line-height: 1.7;
}

/* ============================================================
   layout / 观看期望设置器
   ============================================================ */
.viewing-setup {
  border-top: 1px solid #E6DDD5;
}

.setup-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}

.setup-intro {
  color: #5C534E;
  font-size: 15px;
  line-height: 1.8;
  margin-bottom: 24px;
}

.range-input-row {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 12px;
}

.range-input-row input[type="range"] {
  flex: 1;
  accent-color: #B2232D;
  height: 4px;
  cursor: pointer;
}

.range-input-row input[type="number"] {
  width: 90px;
  padding: 10px 12px;
  border: 1px solid #E6DDD5;
  border-radius: 6px;
  font-size: 15px;
  font-family: inherit;
  background-color: #FFFFFF;
  color: #332A28;
  text-align: center;
}

.range-input-row input[type="number"]:focus {
  border-color: #B2232D;
  outline: none;
}

.setup-hint {
  font-size: 13px;
  color: #8E837C;
  line-height: 1.6;
}

.setup-result {
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  padding: 28px 24px;
  text-align: center;
}

.result-label {
  display: block;
  font-size: 13px;
  color: #8E837C;
  margin-bottom: 10px;
  text-align: left;
}

.result-channel {
  font-family: "SF Mono", "Cascadia Code", Consolas, "Courier New", monospace;
  font-size: 20px;
  font-weight: 700;
  color: #B2232D;
  margin-bottom: 8px;
  font-variant-numeric: tabular-nums;
}

.result-note {
  font-size: 14px;
  color: #6B615B;
  line-height: 1.7;
  text-align: left;
}

/* ============================================================
   layout / 内容时间线
   ============================================================ */
.content-timeline {
  border-top: 1px solid #E6DDD5;
  background-color: #FFFFFF;
}

.content-timeline .section-block {
  max-width: 1180px;
  margin: 0 auto;
  padding-left: 24px;
  padding-right: 24px;
}

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

.timeline-item {
  position: relative;
  padding: 28px 24px 24px;
  background-color: #FBF7F2;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
}

.timeline-item .step-no {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background-color: #B2232D;
  color: #FFFFFF;
  font-size: 14px;
  font-weight: 700;
  border-radius: 50%;
  margin-bottom: 14px;
  font-variant-numeric: tabular-nums;
}

.timeline-item h3 {
  font-size: 17px;
  margin-bottom: 8px;
}

.timeline-item p {
  font-size: 14px;
  color: #6B615B;
  line-height: 1.7;
}

/* ============================================================
   layout / 边界与被引导双入口
   ============================================================ */
.guide-entry {
  border-top: 1px solid #E6DDD5;
}

.entry-card-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.entry-card {
  display: block;
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  padding: 32px 28px;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.entry-card:hover {
  border-color: #B2232D;
  box-shadow: 0 4px 16px rgba(178, 35, 45, 0.08);
}

.entry-card h3 {
  font-size: 18px;
  color: #B2232D;
  margin-bottom: 8px;
}

.entry-card p {
  font-size: 14px;
  color: #6B615B;
  line-height: 1.7;
}

/* ============================================================
   components / 首页通用 section-title 与描述
   ============================================================ */
.section-title {
  font-size: 26px;
  margin-bottom: 12px;
}

.section-desc {
  color: #6B615B;
  margin-bottom: 24px;
  max-width: 680px;
  line-height: 1.8;
}

/* ============================================================
   pages / 频道档案页
   ============================================================ */
.inner-container {
  display: block;
}

.filter-section {
  margin-bottom: 32px;
}

.filter-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.filter-tag {
  display: inline-block;
  padding: 8px 18px;
  border: 1px solid #E6DDD5;
  border-radius: 999px;
  background-color: #FFFFFF;
  font-size: 14px;
  color: #3F3A36;
  cursor: pointer;
  transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
  min-height: 40px;
}

.filter-tag:hover {
  border-color: #B2232D;
  color: #B2232D;
}

.filter-tag.is-active {
  background-color: #B2232D;
  border-color: #B2232D;
  color: #FFFFFF;
  font-weight: 600;
}

.layout-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 40px;
  align-items: start;
}

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

.channel-list-section {
  margin-bottom: 32px;
}

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

.channel-item {
  display: grid;
  grid-template-columns: 90px 1fr;
  gap: 20px;
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  padding: 20px 24px;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.channel-item:hover {
  border-color: #D8C8BE;
  box-shadow: 0 2px 8px rgba(51, 42, 40, 0.05);
}

.channel-item .channel-no {
  align-self: start;
  font-size: 13px;
  padding: 4px 10px;
  margin-bottom: 0;
  text-align: center;
  justify-self: start;
  min-width: 64px;
}

.channel-item .channel-body {
  min-width: 0;
}

.channel-item .channel-name {
  font-size: 17px;
  font-weight: 700;
  color: #332A28;
  margin-bottom: 6px;
}

.channel-item .channel-theme {
  font-size: 14px;
  color: #6B615B;
  line-height: 1.7;
  margin-bottom: 4px;
}

.channel-item .channel-entry {
  font-size: 13px;
  color: #8E837C;
  line-height: 1.6;
}

.channel-map-figure {
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  overflow: hidden;
  margin-top: 8px;
}

.channel-map-figure img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.channel-map-figure figcaption {
  padding: 14px 16px;
  border-top: 1px solid #F0EAE3;
}

.figure-label {
  display: block;
  font-size: 13px;
  color: #6B615B;
  line-height: 1.6;
}

/* 侧栏 */
.sidebar-note {
  min-width: 0;
}

.relation-card {
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  padding: 24px 20px;
}

.relation-title {
  font-size: 18px;
  color: #332A28;
  margin-bottom: 10px;
}

.relation-desc {
  font-size: 14px;
  color: #6B615B;
  line-height: 1.7;
  margin-bottom: 16px;
}

.relation-desc a {
  color: #B2232D;
  font-weight: 500;
}

.relation-desc a:hover {
  text-decoration: underline;
}

.relation-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 18px;
}

.relation-list li {
  font-size: 14px;
  color: #3F3A36;
  padding: 6px 0;
  border-bottom: 1px dashed #F0EAE3;
}

.text-link {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  color: #B2232D;
}

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

/* 频道档案页相关链接 */
.related-links {
  display: flex;
  align-items: center;
  gap: 16px;
  padding-top: 40px;
  padding-bottom: 8px;
  flex-wrap: wrap;
}

.related-links-label {
  font-size: 14px;
  color: #8E837C;
}

.related-links-item {
  font-size: 14px;
  font-weight: 500;
  color: #B2232D;
  border: 1px solid rgba(178, 35, 45, 0.2);
  border-radius: 999px;
  padding: 6px 16px;
  background-color: #FFFFFF;
  transition: background-color 0.2s ease, border-color 0.2s ease;
}

.related-links-item:hover {
  background-color: rgba(178, 35, 45, 0.06);
  border-color: #B2232D;
}

/* ============================================================
   pages / 字段说明页
   ============================================================ */
.page-title-wrap {
  display: flex;
  align-items: baseline;
  gap: 16px;
  flex-wrap: wrap;
}

.page-title-wrap .archive-no {
  margin-bottom: 0;
}

.field-overview {
  margin-bottom: 40px;
}

.overview-statement {
  font-size: 17px;
  line-height: 1.8;
  color: #332A28;
  background-color: #FFFFFF;
  border-left: 4px solid #B2232D;
  border-radius: 0 8px 8px 0;
  padding: 20px 24px;
  margin-bottom: 16px;
}

.field-overview > p:not(.overview-statement) {
  font-size: 15px;
  color: #6B615B;
  line-height: 1.8;
}

.field-index {
  margin-bottom: 40px;
}

.tag-group {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.tag-link {
  display: inline-block;
  padding: 8px 18px;
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 999px;
  font-size: 14px;
  color: #3F3A36;
  transition: border-color 0.2s ease, color 0.2s ease, background-color 0.2s ease;
  min-height: 40px;
}

.tag-link:hover {
  border-color: #B2232D;
  color: #B2232D;
  background-color: rgba(178, 35, 45, 0.04);
}

.field-terms {
  display: flex;
  flex-direction: column;
  gap: 20px;
  margin-bottom: 48px;
}

.term-card {
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  padding: 28px 28px 24px;
}

.term-head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}

.term-code {
  font-family: "SF Mono", "Cascadia Code", Consolas, "Courier New", monospace;
  font-size: 13px;
  font-weight: 600;
  color: #B2232D;
  background-color: rgba(178, 35, 45, 0.07);
  border-radius: 4px;
  padding: 2px 8px;
  font-variant-numeric: tabular-nums;
}

.term-name {
  font-size: 20px;
  color: #332A28;
}

.term-def {
  font-size: 15px;
  color: #3F3A36;
  line-height: 1.8;
  margin-bottom: 18px;
}

.term-example {
  background-color: #FBF7F2;
  border: 1px solid #F0EAE3;
  border-radius: 6px;
  padding: 16px 20px;
  margin-bottom: 16px;
}

.term-example h4 {
  font-size: 13px;
  font-weight: 600;
  color: #8E837C;
  margin-bottom: 6px;
}

.term-example p {
  font-size: 14px;
  color: #3F3A36;
  line-height: 1.7;
}

.term-related {
  display: flex;
  align-items: baseline;
  gap: 10px;
  flex-wrap: wrap;
}

.term-related h4 {
  font-size: 13px;
  color: #8E837C;
  font-weight: 500;
}

.term-related a {
  font-size: 14px;
  color: #B2232D;
  font-weight: 500;
}

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

.field-visual {
  margin-bottom: 48px;
}

.field-figure {
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  overflow: hidden;
  margin-bottom: 12px;
}

.field-figure img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.field-figure figcaption {
  padding: 12px 16px;
  font-size: 13px;
  color: #6B615B;
  border-top: 1px solid #F0EAE3;
}

.field-visual > p {
  font-size: 14px;
  color: #6B615B;
  line-height: 1.7;
}

.extended-reading .related-links {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  padding-top: 0;
}

.related-card {
  display: block;
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  padding: 20px 24px;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.related-card:hover {
  border-color: #B2232D;
  box-shadow: 0 4px 12px rgba(178, 35, 45, 0.06);
}

.related-card-label {
  display: block;
  font-family: "SF Mono", "Cascadia Code", Consolas, "Courier New", monospace;
  font-size: 12px;
  color: #B2232D;
  font-weight: 600;
  margin-bottom: 6px;
  font-variant-numeric: tabular-nums;
}

.related-card-text {
  font-size: 15px;
  color: #3F3A36;
  font-weight: 500;
  line-height: 1.6;
}

/* ============================================================
   pages / 使用示例页
   ============================================================ */
.usage-lead {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: center;
  margin-bottom: 48px;
}

.lead-copy .section-title {
  margin-bottom: 16px;
}

.lead-copy p {
  font-size: 15px;
  color: #6B615B;
  line-height: 1.8;
  margin-bottom: 12px;
}

.lead-media {
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  overflow: hidden;
}

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

.lead-media figcaption {
  padding: 10px 14px;
  font-size: 13px;
  color: #6B615B;
  border-top: 1px solid #F0EAE3;
}

.usage-timeline {
  margin-bottom: 48px;
}

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

.timeline-step {
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  padding: 24px 20px;
}

.timeline-step .step-no {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background-color: #B2232D;
  color: #FFFFFF;
  font-size: 14px;
  font-weight: 700;
  border-radius: 50%;
  margin-bottom: 14px;
  font-variant-numeric: tabular-nums;
}

.timeline-step h3 {
  font-size: 17px;
  margin-bottom: 8px;
}

.timeline-step p {
  font-size: 14px;
  color: #6B615B;
  line-height: 1.7;
}

.usage-scenarios {
  margin-bottom: 48px;
}

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

.scenario-card {
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  padding: 24px 20px;
}

.scenario-card h3 {
  font-size: 17px;
  color: #B2232D;
  margin-bottom: 16px;
}

.scenario-detail {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.detail-row {
  display: grid;
  grid-template-columns: 72px 1fr;
  gap: 12px;
}

.detail-row dt {
  font-size: 13px;
  color: #8E837C;
  font-weight: 500;
  padding-top: 2px;
}

.detail-row dd {
  font-size: 14px;
  color: #3F3A36;
  line-height: 1.7;
  margin: 0;
}

.usage-resources {
  margin-bottom: 48px;
}

.resource-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.resource-card {
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
}

.resource-no {
  font-family: "SF Mono", "Cascadia Code", Consolas, "Courier New", monospace;
  font-size: 12px;
  font-weight: 600;
  color: #B2232D;
  margin-bottom: 8px;
  font-variant-numeric: tabular-nums;
}

.resource-card h3 {
  font-size: 18px;
  margin-bottom: 8px;
}

.resource-card p {
  font-size: 14px;
  color: #6B615B;
  line-height: 1.7;
  flex-grow: 1;
  margin-bottom: 8px;
}

.resource-card a {
  display: inline-flex;
  align-items: center;
  font-size: 14px;
  font-weight: 600;
  color: #B2232D;
}

.resource-card a:hover {
  text-decoration: underline;
}

.usage-further {
  margin-bottom: 16px;
}

.further-links {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.further-links a {
  display: inline-block;
  padding: 8px 18px;
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  color: #B2232D;
  transition: border-color 0.2s ease, background-color 0.2s ease;
}

.further-links a:hover {
  border-color: #B2232D;
  background-color: rgba(178, 35, 45, 0.04);
}

/* ============================================================
   pages / 边界与引用页
   ============================================================ */
.boundary-intro-section,
.boundary-rules-section,
.citation-rules-section,
.boundary-image-section,
.feedback-path-section {
  margin-bottom: 48px;
}

.section-heading h2 {
  font-size: 22px;
  margin-bottom: 16px;
}

.intro-copy p {
  font-size: 15px;
  color: #6B615B;
  line-height: 1.8;
  margin-bottom: 12px;
}

.intro-copy p:last-child {
  margin-bottom: 0;
}

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

.rule-item {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 20px;
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  padding: 20px 24px;
}

.rule-item h3 {
  font-size: 16px;
  color: #B2232D;
  padding-top: 2px;
}

.rule-item p {
  font-size: 14px;
  color: #6B615B;
  line-height: 1.7;
}

.citation-card {
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  padding: 24px 28px;
}

.citation-summary {
  font-size: 15px;
  color: #3F3A36;
  line-height: 1.8;
  margin-bottom: 16px;
}

.citation-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.citation-list li {
  font-size: 14px;
  color: #6B615B;
  line-height: 1.7;
  padding-left: 18px;
  position: relative;
}

.citation-list li::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 12px;
  width: 6px;
  height: 6px;
  background-color: #E8A23C;
  border-radius: 50%;
}

.citation-list strong {
  color: #332A28;
  font-weight: 600;
}

.boundary-figure {
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 8px;
  overflow: hidden;
  margin-bottom: 12px;
}

.boundary-figure img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.boundary-figure figcaption {
  padding: 12px 16px;
  font-size: 13px;
  color: #6B615B;
  border-top: 1px solid #F0EAE3;
}

.figure-note {
  font-size: 14px;
  color: #6B615B;
  line-height: 1.7;
}

.feedback-path-content p {
  font-size: 15px;
  color: #6B615B;
  line-height: 1.8;
  margin-bottom: 12px;
}

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

.path-list li {
  display: inline-block;
}

.path-list a {
  display: inline-block;
  padding: 8px 18px;
  background-color: #FFFFFF;
  border: 1px solid #E6DDD5;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  color: #B2232D;
  transition: border-color 0.2s ease, background-color 0.2s ease;
  min-height: 40px;
}

.path-list a:hover {
  border-color: #B2232D;
  background-color: rgba(178, 35, 45, 0.04);
}

/* ============================================================
   pages / 404 页面
   ============================================================ */
.error-main {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 60vh;
  padding: 48px 24px;
}

.error-panel {
  text-align: center;
  max-width: 560px;
}

.error-code {
  font-family: "SF Mono", "Cascadia Code", Consolas, "Courier New", monospace;
  font-size: 72px;
  font-weight: 700;
  color: #B2232D;
  line-height: 1;
  margin-bottom: 16px;
  font-variant-numeric: tabular-nums;
}

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

.error-desc {
  font-size: 15px;
  color: #6B615B;
  line-height: 1.8;
  margin-bottom: 24px;
}

.error-home-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background-color: #B2232D;
  color: #FFFFFF;
  font-size: 15px;
  font-weight: 600;
  padding: 12px 28px;
  border-radius: 6px;
  transition: background-color 0.2s ease;
  margin-bottom: 16px;
}

.error-home-btn:hover {
  background-color: #8F1A22;
  color: #FFFFFF;
}

.error-help {
  font-size: 13px;
  color: #8E837C;
  line-height: 1.7;
}

/* ============================================================
   responsive / 1024px 断点
   ============================================================ */
@media (max-width: 1024px) {
  .hero-map {
    grid-template-columns: 1fr;
    gap: 32px;
    padding-top: 40px;
  }

  .hero-copy h1 {
    font-size: 34px;
  }

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

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

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

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

  .usage-lead {
    grid-template-columns: 1fr;
    gap: 24px;
  }

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

  .rule-item {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .detail-row {
    grid-template-columns: 60px 1fr;
  }
}

/* ============================================================
   responsive / 640px 断点
   ============================================================ */
@media (max-width: 640px) {
  .header-inner,
  .footer-grid,
  .footer-bottom,
  .hero-map,
  .channel-strip,
  .public-index,
  .viewing-setup,
  .content-timeline,
  .guide-entry,
  .page-header,
  .breadcrumb,
  .inner-container,
  .layout-shell,
  .related-links,
  .usage-lead,
  .usage-timeline,
  .usage-scenarios,
  .usage-resources,
  .usage-further,
  .boundary-intro-section,
  .boundary-rules-section,
  .citation-rules-section,
  .boundary-image-section,
  .feedback-path-section,
  .error-panel {
    padding-left: 16px;
    padding-right: 16px;
  }

  .header-inner {
    min-height: 60px;
    gap: 12px;
  }

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

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: #FFFFFF;
    border-bottom: 1px solid #E6DDD5;
    box-shadow: 0 8px 20px rgba(51, 42, 40, 0.08);
    display: none;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 0;
  }

  .nav-list li {
    border-bottom: 1px solid #F5EFE9;
  }

  .nav-list li:last-child {
    border-bottom: none;
  }

  .nav-list a {
    padding: 14px 20px;
    border-radius: 0;
    white-space: normal;
  }

  .nav-list a.is-current {
    background-color: rgba(178, 35, 45, 0.06);
  }

  .nav-toggle[aria-expanded="true"] + .site-nav {
    display: block;
  }

  .hero-map {
    padding-top: 32px;
    padding-bottom: 32px;
  }

  .hero-copy h1 {
    font-size: 28px;
  }

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

  .section-block {
    padding-top: 40px;
    padding-bottom: 40px;
  }

  .channel-strip h2,
  .public-index h2,
  .viewing-setup h2,
  .content-timeline h2,
  .guide-entry h2 {
    font-size: 22px;
  }

  .channel-card-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

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

  .index-card {
    padding: 16px 14px;
  }

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

  .index-card p {
    font-size: 12px;
  }

  .setup-layout {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .range-input-row {
    flex-wrap: wrap;
  }

  .range-input-row input[type="range"] {
    flex: 1 1 100%;
    order: 2;
  }

  .range-input-row input[type="number"] {
    order: 1;
  }

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

  .entry-card-row {
    grid-template-columns: 1fr;
    gap: 16px;
  }

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

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

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

  .layout-shell {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .content-primary {
    order: 1;
  }

  .sidebar-note {
    order: 2;
  }

  .channel-item {
    grid-template-columns: 1fr;
    gap: 12px;
    padding: 18px 16px;
  }

  .channel-item .channel-no {
    margin-bottom: 0;
  }

  .filter-tags {
    overflow-x: auto;
    flex-wrap: nowrap;
    padding-bottom: 8px;
    -webkit-overflow-scrolling: touch;
  }

  .filter-tag {
    flex-shrink: 0;
  }

  .related-links {
    gap: 10px;
    flex-direction: column;
    align-items: flex-start;
  }

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

  .timeline-steps {
    grid-template-columns: 1fr;
    gap: 16px;
  }

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

  .resource-cards {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .usage-lead {
    margin-bottom: 32px;
  }

  .usage-timeline,
  .usage-scenarios,
  .usage-resources {
    margin-bottom: 32px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 28px;
    padding-top: 40px;
    padding-bottom: 32px;
  }

  .footer-bottom p {
    font-size: 12px;
  }

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

  .citation-card {
    padding: 20px 16px;
  }

  .detail-row {
    grid-template-columns: 1fr;
    gap: 2px;
  }

  .detail-row dt {
    font-size: 12px;
    color: #8E837C;
  }

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

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

  .error-panel h1 {
    font-size: 20px;
  }

  .timeline-item {
    padding: 20px 16px;
  }

  .term-card {
    padding: 20px 16px;
  }

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

  .related-card {
    padding: 16px;
  }

  .feedback-path-content .path-list {
    flex-direction: column;
    align-items: stretch;
  }

  .path-list a {
    text-align: center;
  }

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

/* ============================================================
   responsive / 极小屏 360px 适配
   ============================================================ */
@media (max-width: 380px) {
  .index-grid {
    grid-template-columns: 1fr;
  }

  .range-input-row input[type="number"] {
    width: 100%;
  }

  .brand-link {
    font-size: 16px;
  }

  .nav-toggle {
    width: 40px;
    height: 40px;
  }
}

/* ============================================================
   reduced motion
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}