/* ==========================================================================
   光棍影视 · 全站样式表
   学术期刊风：纸白底、墨黑正文、低饱和靛蓝主色、浅灰细框
   分组：base / layout / components / pages / responsive
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. base · 变量、重置、排版基础
   -------------------------------------------------------------------------- */

:root {
  --paper: #fbfaf7;
  --ink: #1f2328;
  --indigo: #3b5b8c;
  --indigo-dark: #2c4670;
  --grey: #8a8f98;
  --line: #e3e0d8;
  --line-strong: #cfcabd;
  --paper-sunk: #f5f3ee;

  --font-serif: "Songti SC", "Noto Serif SC", "Source Han Serif SC", "SimSun", Georgia, serif;
  --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SFMono-Regular", Menlo, Consolas, "Courier New", monospace;

  --shell: 1120px;
  --read: 720px;
  --side: 320px;
  --gap: 80px;
  --radius: 6px;
}

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

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

.site-body {
  margin: 0;
  background-color: var(--paper);
  color: var(--ink);
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 1.85;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3,
h4 {
  margin: 0;
  font-family: var(--font-sans);
  font-weight: 700;
  line-height: 1.35;
  color: var(--ink);
}

p {
  margin: 0;
}

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

dl,
dd,
dt {
  margin: 0;
}

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

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

a:hover {
  color: var(--indigo-dark);
  text-decoration: underline;
}

a:focus-visible,
button:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--indigo);
  outline-offset: 3px;
}

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  cursor: pointer;
}

table {
  border-collapse: collapse;
  width: 100%;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  padding: 10px 16px;
  background-color: var(--ink);
  color: var(--paper);
  font-family: var(--font-sans);
  font-size: 14px;
  z-index: 60;
}

.skip-link:focus {
  left: 12px;
  top: 12px;
  color: var(--paper);
  text-decoration: none;
}

/* --------------------------------------------------------------------------
   2. layout · 页头、主导航、主容器、页脚骨架
   -------------------------------------------------------------------------- */

/* 页头 */
.site-header {
  position: relative;
  z-index: 40;
  background-color: var(--paper);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 0 24px;
  min-height: 76px;
  display: flex;
  align-items: center;
  gap: 32px;
}

.brand {
  display: flex;
  align-items: baseline;
  gap: 10px;
  flex: 0 0 auto;
  text-decoration: none;
}

.brand:hover {
  text-decoration: none;
}

.brand-mark {
  font-family: var(--font-sans);
  font-size: 21px;
  font-weight: 700;
  color: var(--ink);
}

.brand-sub {
  font-family: var(--font-sans);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--grey);
}

/* 主导航 */
.site-nav {
  margin-left: auto;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
  font-family: var(--font-sans);
  font-size: 14px;
}

.nav-group {
  position: relative;
}

.nav-group-toggle {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 44px;
  padding: 0 14px;
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--ink);
  border-radius: var(--radius);
}

.nav-group-toggle::after {
  content: "";
  width: 6px;
  height: 6px;
  border-right: 1.5px solid var(--grey);
  border-bottom: 1.5px solid var(--grey);
  transform: rotate(45deg) translateY(-2px);
}

.nav-group-toggle:hover {
  color: var(--indigo);
  background-color: var(--paper-sunk);
}

.nav-sub {
  position: absolute;
  left: 0;
  top: 100%;
  min-width: 176px;
  padding: 8px;
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: 0 8px 20px rgba(31, 35, 40, 0.07);
  display: none;
}

.nav-group.is-open .nav-sub,
.nav-group:hover .nav-sub {
  display: block;
}

.nav-sub a {
  display: block;
  padding: 9px 12px;
  min-height: 44px;
  font-size: 14px;
  color: var(--ink);
  border-radius: 4px;
}

.nav-sub a:hover {
  background-color: var(--paper-sunk);
  color: var(--indigo);
  text-decoration: none;
}

.nav-sub a.is-current {
  color: var(--indigo);
  font-weight: 700;
}

/* 汉堡按钮：桌面隐藏 */
.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 11px 10px;
  flex-direction: column;
  justify-content: space-between;
  border-radius: var(--radius);
  margin-left: auto;
}

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

/* 主容器 */
.site-main {
  display: block;
}

.inner-main {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 28px 24px 72px;
}

/* 页脚 */
.site-footer {
  background-color: var(--paper-sunk);
  border-top: 1px solid var(--line);
  margin-top: 24px;
}

.footer-inner {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 48px 24px 28px;
  display: grid;
  grid-template-columns: minmax(240px, 1.4fr) repeat(3, minmax(120px, 1fr));
  gap: 40px 32px;
}

.footer-name {
  font-family: var(--font-sans);
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
}

.footer-desc {
  margin-top: 10px;
  max-width: 300px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--grey);
}

.footer-group-title {
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--grey);
}

.footer-group ul {
  margin-top: 14px;
}

.footer-group li + li {
  margin-top: 8px;
}

.footer-group a {
  display: inline-block;
  padding: 4px 0;
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--ink);
}

.footer-group a:hover {
  color: var(--indigo);
}

.footer-bottom {
  grid-column: 1 / -1;
  margin-top: 8px;
  padding-top: 20px;
  border-top: 1px solid var(--line-strong);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 24px;
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--grey);
}

.footer-note {
  flex: 1 1 320px;
  min-width: 220px;
  line-height: 1.7;
}

.footer-copy {
  flex: 0 0 auto;
}

.back-top {
  flex: 0 0 auto;
  margin-left: auto;
  padding: 6px 0;
  color: var(--indigo);
}

/* --------------------------------------------------------------------------
   3. components · 通用组件（按钮、摘要、表格、清单、卡片）
   -------------------------------------------------------------------------- */

.btn-primary,
.btn-ghost,
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 20px;
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 700;
  border-radius: var(--radius);
}

.btn-primary,
.btn.btn-primary {
  background-color: var(--indigo);
  color: #fff;
  border: 1px solid var(--indigo);
}

.btn-primary:hover,
.btn.btn-primary:hover {
  background-color: var(--indigo-dark);
  border-color: var(--indigo-dark);
  color: #fff;
  text-decoration: none;
}

.btn-ghost,
.btn.btn-ghost {
  background-color: transparent;
  color: var(--ink);
  border: 1px solid var(--line-strong);
}

.btn-ghost:hover,
.btn.btn-ghost:hover {
  border-color: var(--indigo);
  color: var(--indigo);
  text-decoration: none;
}

/* 摘要区：浅底细框 + 左侧竖线 */
.section-lead,
.hero-lead,
.page-summary {
  color: #3a3f45;
}

.page-summary,
.section-lead {
  border-left: 3px solid var(--line-strong);
  background-color: var(--paper-sunk);
  padding: 14px 18px;
  font-size: 15px;
  line-height: 1.8;
  border-radius: 0 var(--radius) var(--radius) 0;
}

/* 区块通用 */
.section + .section {
  margin-top: 64px;
}

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

.section-head {
  margin-bottom: 28px;
}

.section-head .section-title {
  font-size: 24px;
}

.section-intro {
  margin-top: 10px;
  font-size: 16px;
  line-height: 1.85;
  color: #3a3f45;
}

.section-title + .section-lead {
  margin-top: 14px;
}

.section-lead + * {
  margin-top: 24px;
}

.section-note,
.boundary-note,
.feedback-note {
  margin-top: 22px;
  padding: 14px 18px;
  background-color: var(--paper-sunk);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-size: 15px;
  line-height: 1.8;
  color: #3a3f45;
}

/* 表格 */
.field-table,
.mapping-table {
  font-family: var(--font-sans);
  font-size: 14px;
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.field-table caption,
.table-caption {
  padding: 12px 16px;
  text-align: left;
  font-size: 13px;
  color: var(--grey);
  background-color: var(--paper-sunk);
  border-bottom: 1px solid var(--line);
}

.field-table th,
.field-table td,
.mapping-table th,
.mapping-table td {
  padding: 12px 16px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--line);
  line-height: 1.7;
}

.field-table thead th,
.mapping-table thead th {
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--grey);
  background-color: var(--paper-sunk);
}

.field-table tbody th,
.mapping-table tbody th {
  font-weight: 700;
  color: var(--ink);
  white-space: nowrap;
}

.field-table tbody tr:last-child th,
.field-table tbody tr:last-child td,
.mapping-table tbody tr:last-child th,
.mapping-table tbody tr:last-child td {
  border-bottom: 0;
}

.field-table tbody tr:hover,
.mapping-table tbody tr:hover {
  background-color: #f8f7f3;
}

.table-wrap {
  overflow-x: auto;
  border-radius: var(--radius);
}

/* 编号清单 */
.rule-list {
  counter-reset: rule;
}

.rule-item {
  position: relative;
  padding: 16px 0 16px 46px;
  border-bottom: 1px solid var(--line);
}

.rule-item:last-child {
  border-bottom: 0;
}

.rule-item::before {
  counter-increment: rule;
  content: counter(rule, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 16px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--grey);
}

.rule-title {
  font-size: 17px;
}

.rule-text,
.rule-body p {
  margin-top: 6px;
  font-size: 16px;
  line-height: 1.8;
  color: #3a3f45;
}

.rule-num {
  position: absolute;
  left: 0;
  top: 2px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--grey);
}

.rule-body {
  position: relative;
}

/* 相关入口条 */
.related-bar {
  margin-top: 64px;
  padding: 24px 26px;
  background-color: var(--paper-sunk);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.related-title {
  font-size: 15px;
  letter-spacing: 0.06em;
  color: var(--grey);
}

.related-list {
  margin-top: 16px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 10px 20px;
}

.related-item a {
  display: block;
  padding: 8px 0;
  font-family: var(--font-sans);
  font-size: 15px;
}

.related-item a::before {
  content: "→ ";
  color: var(--grey);
}

.related-label {
  display: block;
  margin-bottom: 14px;
  font-family: var(--font-sans);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--grey);
}

/* 面包屑与页标题区 */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--grey);
}

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

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

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

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

.page-header {
  margin: 18px 0 44px;
}

.page-description {
  font-family: var(--font-sans);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--grey);
}

.page-title {
  margin-top: 8px;
  font-size: 32px;
  font-weight: 700;
  color: var(--ink);
}

.page-summary {
  margin-top: 18px;
  max-width: var(--read);
}

/* 图片容器 */
figure {
  margin: 0;
}

.hero-figure,
.content-media,
.channel-figure,
.playlist-cover,
.media-figure,
.path-figure {
  overflow: hidden;
  border-radius: var(--radius);
  background-color: var(--paper-sunk);
}

.hero-figure img,
.content-media img,
.channel-figure img,
.playlist-cover img,
.media-figure img,
.path-figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

figcaption,
.channel-figcaption {
  margin-top: 10px;
  font-family: var(--font-sans);
  font-size: 13px;
  line-height: 1.7;
  color: var(--grey);
}

/* 记录清单 */
.log-list {
  border-top: 1px solid var(--line);
}

.log-item {
  display: grid;
  grid-template-columns: 120px 120px 1fr;
  gap: 8px 20px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
  font-size: 16px;
}

.log-date {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--grey);
  padding-top: 4px;
}

.log-type {
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--indigo);
  padding-top: 4px;
}

.log-text,
.log-desc {
  line-height: 1.8;
  color: #3a3f45;
}

/* FAQ 折叠 */
.faq-list {
  border-top: 1px solid var(--line);
}

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

.faq-question {
  position: relative;
  padding: 18px 44px 18px 0;
  font-family: var(--font-sans);
  font-size: 17px;
  font-weight: 700;
  cursor: pointer;
  list-style: none;
}

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

.faq-question::after {
  content: "+";
  position: absolute;
  right: 6px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 20px;
  font-weight: 400;
  color: var(--grey);
}

.faq-item[open] .faq-question::after {
  content: "–";
}

.faq-answer {
  padding: 0 0 20px;
  font-size: 16px;
  line-height: 1.85;
  color: #3a3f45;
}

/* --------------------------------------------------------------------------
   4. pages · 首页
   -------------------------------------------------------------------------- */

.home-main {
  display: block;
}

.hero {
  border-bottom: 1px solid var(--line);
}

.hero-inner {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 56px 24px 40px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 460px);
  gap: 56px;
  align-items: start;
}

.hero-eyebrow {
  font-family: var(--font-sans);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--grey);
}

.hero-title {
  margin-top: 12px;
  font-size: 38px;
  font-weight: 700;
  line-height: 1.3;
}

.hero-lead {
  margin-top: 18px;
  max-width: 560px;
  font-size: 17px;
  line-height: 1.85;
}

.hero-tags {
  margin-top: 24px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 14px;
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--ink);
  background-color: var(--paper-sunk);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.tag-link:hover {
  border-color: var(--indigo);
  color: var(--indigo);
  text-decoration: none;
}

.hero-cta {
  margin-top: 28px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.hero-figure {
  border: 1px solid var(--line);
}

.hero-figure img {
  aspect-ratio: 4 / 3;
}

.content-media {
  max-width: var(--shell);
  margin: 40px auto 0;
  padding: 0 24px;
  background-color: transparent;
}

.content-media img {
  aspect-ratio: 21 / 9;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.channel-overview,
.topic-overview,
.field-summary,
.path-overview,
.changelog {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 0 24px;
}

.channel-overview {
  margin-top: 72px;
}

/* 频道方向总览：主次网格 */
.channel-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 20px;
}

.channel-item {
  padding: 22px 20px;
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.channel-item:hover {
  border-color: var(--line-strong);
}

.channel-item-featured {
  grid-column: span 2;
  background-color: var(--paper-sunk);
}

.channel-name {
  font-size: 19px;
}

.channel-name a {
  color: var(--ink);
}

.channel-name a:hover {
  color: var(--indigo);
}

.channel-scope {
  margin-top: 10px;
  font-size: 16px;
  line-height: 1.8;
  color: #3a3f45;
}

.channel-meta {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  display: grid;
  grid-template-columns: 88px minmax(0, 1fr);
  gap: 6px 12px;
  font-family: var(--font-sans);
  font-size: 13px;
}

.channel-meta dt {
  color: var(--grey);
}

.channel-meta dd {
  color: var(--ink);
  line-height: 1.7;
}

/* 专题片单速览 */
.topic-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

.topic-card {
  display: flex;
  flex-direction: column;
  padding: 24px 22px;
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.topic-name {
  font-size: 19px;
}

.topic-name a {
  color: var(--ink);
}

.topic-name a:hover {
  color: var(--indigo);
}

.topic-scope {
  margin-top: 12px;
  font-size: 16px;
  line-height: 1.8;
  color: #3a3f45;
}

.topic-channel,
.topic-count {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--line);
  font-family: var(--font-sans);
  font-size: 13px;
  line-height: 1.7;
  color: var(--grey);
}

/* 查阅路径三步概览 */
.step-list {
  counter-reset: step;
  border-top: 1px solid var(--line);
}

.step-item {
  position: relative;
  padding: 20px 0 20px 56px;
  border-bottom: 1px solid var(--line);
}

.step-item::before {
  counter-increment: step;
  content: counter(step, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 22px;
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--indigo);
}

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

.step-goal {
  margin-top: 6px;
  font-size: 16px;
  line-height: 1.8;
  color: #3a3f45;
}

.step-rule {
  margin-top: 6px;
  font-family: var(--font-sans);
  font-size: 13px;
  line-height: 1.7;
  color: var(--grey);
}

.path-cta {
  margin-top: 24px;
}

/* 站内调整记录 */
.changelog {
  margin-top: 64px;
}

.changelog .log-item {
  grid-template-columns: 120px 140px 1fr;
}

.changelog .log-date {
  font-family: var(--font-mono);
}

/* --------------------------------------------------------------------------
   5. pages · 内页共用与各栏目
   -------------------------------------------------------------------------- */

/* 频道分类页：侧栏在左 */
.page-layout {
  display: block;
}

.layout-shell {
  display: grid;
  grid-template-columns: 240px minmax(0, var(--read));
  gap: 56px;
  align-items: start;
}

.channel-index {
  position: sticky;
  top: 24px;
  padding: 20px 18px;
  background-color: var(--paper-sunk);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.aside-title {
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--grey);
}

.channel-index-list {
  margin-top: 14px;
}

.channel-index-item + .channel-index-item {
  border-top: 1px solid var(--line);
}

.channel-index-item a {
  display: block;
  padding: 9px 0;
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--ink);
}

.channel-index-item a:hover {
  color: var(--indigo);
}

.aside-note {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  line-height: 1.7;
  color: var(--grey);
}

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

/* 频道区块 */
.channel-block {
  display: grid;
  grid-template-columns: 240px minmax(0, 1fr);
  gap: 24px;
  padding: 26px 0;
  border-top: 1px solid var(--line);
}

.channel-block:last-child {
  border-bottom: 1px solid var(--line);
}

.channel-figure {
  border: 1px solid var(--line);
}

.channel-figure img {
  aspect-ratio: 3 / 2;
}

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

.channel-fields {
  margin-top: 14px;
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: 8px 14px;
  font-size: 15px;
}

.channel-fields dt {
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--grey);
  padding-top: 3px;
}

.channel-fields dd {
  line-height: 1.8;
  color: #3a3f45;
}

.field-label {
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--grey);
}

.field-value {
  line-height: 1.8;
  color: #3a3f45;
}

/* 频道选择建议 */
.advice-list {
  border-top: 1px solid var(--line);
}

.advice-item {
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.advice-title {
  font-size: 17px;
}

.advice-text {
  margin-top: 6px;
  font-size: 16px;
  line-height: 1.8;
  color: #3a3f45;
}

/* 专题片单页 */
.section-playlists .playlist-block {
  display: grid;
  grid-template-columns: 240px minmax(0, 1fr);
  gap: 28px;
  padding: 28px 0;
  border-top: 1px solid var(--line);
}

.section-playlists .playlist-block:last-child {
  border-bottom: 1px solid var(--line);
}

.playlist-cover {
  border: 1px solid var(--line);
}

.playlist-cover img {
  aspect-ratio: 16 / 10;
}

.playlist-body {
  min-width: 0;
}

.playlist-title {
  font-size: 20px;
}

.playlist-meta {
  margin-top: 14px;
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: 8px 14px;
  font-size: 15px;
}

.playlist-meta dt {
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--grey);
  padding-top: 3px;
}

.playlist-meta dd {
  line-height: 1.8;
  color: #3a3f45;
}

.scope-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 32px;
}

.scope-col {
  padding: 22px;
  background-color: var(--paper-sunk);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.scope-title {
  font-size: 17px;
}

.scope-col p {
  margin-top: 10px;
  font-size: 16px;
  line-height: 1.8;
  color: #3a3f45;
}

.relation-links {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

.relation-link {
  display: block;
  padding: 20px 22px;
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.relation-link:hover {
  border-color: var(--indigo);
  text-decoration: none;
}

.relation-link-label {
  display: block;
  font-family: var(--font-sans);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--grey);
}

.relation-link-title {
  display: block;
  margin-top: 8px;
  font-family: var(--font-sans);
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
}

.relation-link-desc {
  display: block;
  margin-top: 8px;
  font-size: 15px;
  line-height: 1.8;
  color: #3a3f45;
}

/* 条目字段说明页 */
.section-field-overview .media-figure {
  margin-top: 24px;
  border: 1px solid var(--line);
}

.media-figure img {
  aspect-ratio: 21 / 9;
}

.layer-list {
  margin-top: 28px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.layer-item {
  padding: 18px 20px;
  background-color: var(--paper-sunk);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.layer-name {
  font-size: 16px;
}

.layer-desc {
  margin-top: 8px;
  font-size: 15px;
  line-height: 1.8;
  color: #3a3f45;
}

.field-block {
  padding: 22px 0;
  border-top: 1px solid var(--line);
}

.field-block:last-child {
  border-bottom: 1px solid var(--line);
}

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

.field-meaning,
.field-range,
.field-render {
  margin-top: 8px;
  font-size: 16px;
  line-height: 1.85;
  color: #3a3f45;
}

.field-range,
.field-render {
  padding-left: 14px;
  border-left: 2px solid var(--line);
  font-size: 15px;
}

.rule-columns {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 32px;
}

.rule-column {
  padding: 22px;
  background-color: var(--paper-sunk);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.rule-column-title {
  font-size: 17px;
}

.rule-column .rule-list {
  margin-top: 14px;
}

.rule-column .rule-list li {
  position: relative;
  padding-left: 18px;
  margin-top: 10px;
  font-size: 15px;
  line-height: 1.8;
  color: #3a3f45;
}

.rule-column .rule-list li::before {
  content: "·";
  position: absolute;
  left: 4px;
  color: var(--grey);
}

.boundary-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 18px;
}

.boundary-item {
  padding: 20px;
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.boundary-name {
  font-size: 16px;
}

.boundary-desc {
  margin-top: 8px;
  font-size: 15px;
  line-height: 1.8;
  color: #3a3f45;
}

/* 查阅路径页 */
.page-guide .page-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 56px;
  align-items: start;
}

.content-main {
  min-width: 0;
  max-width: var(--read);
}

.content-sidebar {
  position: sticky;
  top: 24px;
  padding: 22px 20px;
  background-color: var(--paper-sunk);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.sidebar-title {
  font-size: 15px;
  letter-spacing: 0.06em;
  color: var(--grey);
}

.sidebar-note {
  margin-top: 12px;
  font-size: 14px;
  line-height: 1.8;
  color: #3a3f45;
}

.sidebar-links {
  margin-top: 16px;
  border-top: 1px solid var(--line);
}

.sidebar-links li {
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
}

.sidebar-links a {
  display: block;
  font-family: var(--font-sans);
  font-size: 15px;
}

.sidebar-desc {
  display: block;
  margin-top: 4px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--grey);
}

.path-figure {
  margin-top: 24px;
  border: 1px solid var(--line);
}

.path-figure img {
  aspect-ratio: 16 / 7;
}

.path-timeline {
  margin-top: 32px;
  border-left: 2px solid var(--line);
  padding-left: 28px;
}

.path-step {
  position: relative;
  padding-bottom: 30px;
}

.path-step:last-child {
  padding-bottom: 0;
}

.path-step::before {
  content: "";
  position: absolute;
  left: -35px;
  top: 8px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background-color: var(--paper);
  border: 2px solid var(--indigo);
}

.path-step .step-index {
  display: block;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--indigo);
}

.path-step .step-body {
  margin-top: 6px;
}

.path-step .step-name {
  font-size: 18px;
}

.path-step .step-desc {
  margin-top: 6px;
  font-size: 16px;
  line-height: 1.8;
  color: #3a3f45;
}

.section-foot {
  margin-top: 28px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px 24px;
  font-family: var(--font-sans);
  font-size: 14px;
}

.step-detail {
  padding: 22px 0;
  border-top: 1px solid var(--line);
}

.step-detail:last-child {
  border-bottom: 1px solid var(--line);
}

.step-detail-name {
  font-size: 18px;
}

.step-detail-list {
  margin-top: 12px;
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: 8px 16px;
  font-size: 15px;
}

.step-detail-list dt {
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--grey);
  padding-top: 3px;
}

.step-detail-list dd {
  line-height: 1.8;
  color: #3a3f45;
}

.stuck-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 18px;
}

.stuck-item {
  padding: 20px;
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.stuck-name {
  font-size: 16px;
}

.stuck-symptom {
  margin-top: 8px;
  font-size: 15px;
  line-height: 1.8;
  color: #3a3f45;
}

.stuck-workaround {
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px solid var(--line);
  font-size: 15px;
  line-height: 1.8;
  color: var(--indigo);
}

.section-log .log-item {
  grid-template-columns: 120px 120px minmax(0, 1fr);
}

.section-log .feedback-note {
  margin-top: 24px;
}

.feedback-title {
  font-size: 16px;
}

.feedback-note p {
  margin-top: 8px;
  font-size: 15px;
  line-height: 1.8;
}

/* 404 */
.error-main {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 72px 24px;
}

.error-panel {
  max-width: 620px;
  padding: 40px 40px 36px;
  background-color: var(--paper-sunk);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.error-code {
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.16em;
  color: var(--grey);
}

.error-title {
  margin-top: 12px;
  font-size: 32px;
}

.error-text {
  margin-top: 16px;
  font-size: 17px;
  line-height: 1.85;
  color: #3a3f45;
}

.error-actions {
  margin-top: 28px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.error-links {
  margin-top: 56px;
  max-width: 620px;
}

.error-links-title {
  font-size: 17px;
}

.error-links-list {
  margin-top: 18px;
  border-top: 1px solid var(--line);
}

.error-links-list li {
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.error-links-list a {
  font-family: var(--font-sans);
  font-size: 16px;
}

.error-links-list span {
  display: block;
  margin-top: 4px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--grey);
}

/* --------------------------------------------------------------------------
   6. responsive · 1024 / 768 / 480
   -------------------------------------------------------------------------- */

@media (max-width: 1024px) {
  :root {
    --gap: 48px;
  }

  .hero-inner {
    grid-template-columns: minmax(0, 1fr) minmax(0, 380px);
    gap: 40px;
    padding-top: 44px;
  }

  .hero-title {
    font-size: 33px;
  }

  .layout-shell {
    grid-template-columns: 210px minmax(0, 1fr);
    gap: 36px;
  }

  .page-guide .page-layout {
    grid-template-columns: minmax(0, 1fr) 260px;
    gap: 40px;
  }

  .channel-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .channel-item-featured {
    grid-column: span 2;
  }

  .topic-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .layer-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .footer-inner {
    grid-template-columns: minmax(220px, 1.4fr) repeat(3, minmax(110px, 1fr));
    gap: 32px 24px;
  }
}

@media (max-width: 768px) {
  .header-inner {
    min-height: 64px;
    padding: 0 18px;
    gap: 16px;
    flex-wrap: wrap;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    flex: 1 0 100%;
    margin-left: 0;
  }

  .nav-list {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 0 16px;
    border-top: 1px solid var(--line);
  }

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

  .nav-group {
    border-bottom: 1px solid var(--line);
  }

  .nav-group-toggle {
    width: 100%;
    justify-content: space-between;
    padding: 0 4px;
    font-size: 15px;
  }

  .nav-sub {
    position: static;
    display: none;
    min-width: 0;
    padding: 0 0 10px 12px;
    border: 0;
    box-shadow: none;
    background-color: transparent;
  }

  .nav-group.is-open .nav-sub {
    display: block;
  }

  .nav-group:hover .nav-sub {
    display: none;
  }

  .nav-group.is-open:hover .nav-sub {
    display: block;
  }

  .nav-sub a {
    padding: 10px 8px;
    font-size: 14px;
    color: #3a3f45;
  }

  .inner-main {
    padding: 20px 18px 56px;
  }

  .hero-inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
    padding: 32px 18px 28px;
  }

  .hero-title {
    font-size: 28px;
  }

  .hero-figure {
    order: 2;
  }

  .content-media {
    padding: 0 18px;
    margin-top: 28px;
  }

  .channel-overview,
  .topic-overview,
  .field-summary,
  .path-overview,
  .changelog {
    padding: 0 18px;
  }

  .channel-overview {
    margin-top: 48px;
  }

  .section + .section {
    margin-top: 44px;
  }

  .section-title,
  .section-head .section-title {
    font-size: 21px;
  }

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

  .page-header {
    margin: 14px 0 32px;
  }

  .channel-grid,
  .topic-grid,
  .layer-list,
  .scope-grid,
  .rule-columns {
    grid-template-columns: minmax(0, 1fr);
  }

  .channel-item-featured {
    grid-column: auto;
  }

  .layout-shell {
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
  }

  .channel-index {
    position: static;
  }

  .channel-index-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    border-top: 0;
  }

  .channel-index-item + .channel-index-item {
    border-top: 0;
  }

  .channel-index-item a {
    padding: 8px 12px;
    min-height: 44px;
    display: inline-flex;
    align-items: center;
    background-color: var(--paper);
    border: 1px solid var(--line);
    border-radius: var(--radius);
  }

  .channel-block,
  .section-playlists .playlist-block {
    grid-template-columns: minmax(0, 1fr);
    gap: 18px;
  }

  .channel-fields,
  .playlist-meta,
  .step-detail-list {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px 0;
  }

  .channel-fields dt,
  .playlist-meta dt,
  .step-detail-list dt {
    padding-top: 8px;
  }

  .page-guide .page-layout {
    grid-template-columns: minmax(0, 1fr);
    gap: 36px;
  }

  .content-main {
    max-width: none;
  }

  .content-sidebar {
    position: static;
  }

  .log-item,
  .changelog .log-item,
  .section-log .log-item {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px;
  }

  .log-date,
  .log-type {
    padding-top: 0;
  }

  .footer-inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 28px 20px;
    padding: 36px 18px 24px;
  }

  .footer-brand {
    grid-column: 1 / -1;
  }

  .footer-desc {
    max-width: none;
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .back-top {
    margin-left: 0;
  }

  .error-main {
    padding: 44px 18px;
  }

  .error-panel {
    padding: 28px 22px;
  }

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

@media (max-width: 480px) {
  .site-body {
    font-size: 16px;
  }

  .brand-sub {
    display: none;
  }

  .hero-title {
    font-size: 25px;
  }

  .hero-lead {
    font-size: 16px;
  }

  .hero-cta .btn-primary,
  .hero-cta .btn-ghost,
  .error-actions .btn {
    width: 100%;
  }

  .page-summary,
  .section-lead {
    padding: 12px 14px;
    font-size: 15px;
  }

  .field-table,
  .mapping-table {
    font-size: 13px;
  }

  .field-table th,
  .field-table td,
  .mapping-table th,
  .mapping-table td {
    padding: 10px 12px;
  }

  .field-table tbody th,
  .mapping-table tbody th {
    white-space: normal;
  }

  .path-timeline {
    padding-left: 22px;
  }

  .path-step::before {
    left: -29px;
  }

  .footer-inner {
    grid-template-columns: minmax(0, 1fr);
  }
}

/* 动效：仅作增强，不影响初始可见性 */
@media (prefers-reduced-motion: no-preference) {
  .channel-item,
  .topic-card,
  .related-item a,
  .relation-link,
  .tag-link {
    transition: border-color 0.18s ease, color 0.18s ease, background-color 0.18s ease;
  }
}