/* ==========================================================================
   九九免费视频 · 全站样式表
   结构：base / layout / components / pages / responsive
   ========================================================================== */

/* --------------------------------------------------------------------------
   base · 基础重置与全局排版
   -------------------------------------------------------------------------- */

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

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

body {
  margin: 0;
  background-color: #f7f8fa;
  color: #1f2a37;
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans CJK SC", system-ui, -apple-system, "Segoe UI", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.75;
  font-weight: 400;
}

h1,
h2,
h3,
h4 {
  margin: 0;
  font-weight: 600;
  line-height: 1.4;
  color: #1f2a37;
}

p {
  margin: 0;
}

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

figure {
  margin: 0;
}

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

a {
  color: #2f6f8f;
  text-decoration: none;
  transition: color 0.18s ease, border-color 0.18s ease;
}

a:hover,
a:focus-visible {
  color: #e07a3f;
}

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

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

code,
time,
.num,
.step-index,
.topic-meta dd {
  font-family: "SFMono-Regular", "JetBrains Mono", Menlo, Consolas, "Courier New", monospace;
}

:focus-visible {
  outline: 2px solid #2f6f8f;
  outline-offset: 2px;
}

/* --------------------------------------------------------------------------
   layout · 页头 / 导航 / 主容器 / 页脚骨架
   -------------------------------------------------------------------------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background-color: #ffffff;
  border-bottom: 1px solid #d8dee5;
}

.header-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
  min-height: 66px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 1px;
  color: #1f2a37;
  padding: 8px 0;
}

.brand:hover,
.brand:focus-visible {
  color: #1f2a37;
}

.brand-name {
  font-size: 19px;
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: 0;
}

.brand-slogan {
  font-size: 12px;
  color: #5b6b7c;
  line-height: 1.4;
}

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

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

.nav-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 12px;
  font-size: 15px;
  color: #1f2a37;
  border-bottom: 2px solid transparent;
  transition: color 0.18s ease, border-color 0.18s ease;
}

.nav-link:hover,
.nav-link:focus-visible {
  color: #2f6f8f;
}

.nav-link.is-current {
  color: #2f6f8f;
  font-weight: 600;
  border-bottom-color: #2f6f8f;
}

.nav-link-sub {
  color: #5b6b7c;
  font-size: 14px;
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  background-color: #1f2a37;
}

.site-main {
  display: block;
}

.home-main,
.inner-main {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

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

/* 面包屑 */

.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  font-size: 13px;
  color: #5b6b7c;
  margin-bottom: 18px;
}

.breadcrumb-list {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
}

.breadcrumb-item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.breadcrumb-item + .breadcrumb-item::before {
  content: "/";
  color: #d8dee5;
}

.breadcrumb-sep {
  color: #d8dee5;
}

.breadcrumb-current {
  color: #5b6b7c;
}

.breadcrumb a {
  color: #2f6f8f;
}

.breadcrumb a:hover,
.breadcrumb a:focus-visible {
  color: #e07a3f;
}

/* 内页标题区 */

.page-header {
  padding-bottom: 20px;
  margin-bottom: 26px;
  border-bottom: 1px solid #d8dee5;
}

.page-title {
  font-size: 28px;
  font-weight: 600;
  color: #1f2a37;
  margin-bottom: 10px;
}

.page-description {
  font-size: 15px;
  color: #5b6b7c;
  max-width: 760px;
}

/* 页脚 */

.site-footer {
  margin-top: 56px;
  background-color: #ffffff;
  border-top: 1px solid #d8dee5;
}

.footer-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 40px 24px 28px;
  display: grid;
  grid-template-columns: minmax(240px, 1.4fr) repeat(3, minmax(140px, 1fr));
  gap: 28px 32px;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.footer-name {
  font-size: 16px;
  font-weight: 600;
  color: #1f2a37;
}

.footer-desc {
  font-size: 13px;
  color: #5b6b7c;
  line-height: 1.7;
}

.footer-group {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-title {
  font-size: 14px;
  font-weight: 600;
  color: #1f2a37;
}

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

.footer-list a {
  display: inline-block;
  font-size: 13px;
  color: #5b6b7c;
  padding: 3px 0;
}

.footer-list a:hover,
.footer-list a:focus-visible {
  color: #2f6f8f;
}

.footer-copy {
  max-width: 1120px;
  margin: 0 auto;
  padding: 16px 24px 30px;
  font-size: 12px;
  color: #5b6b7c;
  border-top: 1px solid #d8dee5;
}

/* --------------------------------------------------------------------------
   components · 通用区块、按钮、卡片、标签
   -------------------------------------------------------------------------- */

.section {
  padding: 34px 0;
  border-top: 1px solid #d8dee5;
}

.section:first-of-type {
  border-top: 0;
}

.section-head {
  margin-bottom: 20px;
}

.section-title {
  font-size: 20px;
  font-weight: 600;
  color: #1f2a37;
  margin-bottom: 10px;
}

.section-desc,
.section-intro,
.section-lead {
  font-size: 14px;
  color: #5b6b7c;
  max-width: 780px;
}

.section-intro,
.section-lead {
  margin-bottom: 18px;
}

.section-more {
  margin-top: 18px;
  font-size: 14px;
}

.link-more {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: #2f6f8f;
  border-bottom: 1px solid #d8dee5;
  padding-bottom: 2px;
}

.link-more::after {
  content: "→";
  font-size: 13px;
}

.link-more:hover,
.link-more:focus-visible {
  color: #e07a3f;
  border-bottom-color: #e07a3f;
}

/* 按钮 */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 20px;
  font-size: 15px;
  font-weight: 600;
  border-radius: 4px;
  border: 1px solid transparent;
  transition: background-color 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}

.btn-primary {
  background-color: #2f6f8f;
  color: #ffffff;
  border-color: #2f6f8f;
}

.btn-primary:hover,
.btn-primary:focus-visible {
  background-color: #245a75;
  border-color: #245a75;
  color: #ffffff;
}

.btn-ghost {
  background-color: #ffffff;
  color: #2f6f8f;
  border-color: #d8dee5;
}

.btn-ghost:hover,
.btn-ghost:focus-visible {
  color: #e07a3f;
  border-color: #e07a3f;
}

/* 图片容器统一约束 */

.hero-media,
.content-media,
.channel-figure,
.topic-figure,
.guide-figure,
.scope-figure,
.section-figure {
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
  overflow: hidden;
}

.hero-media img,
.content-media img,
.channel-figure img,
.topic-figure img,
.guide-figure img,
.scope-figure img,
.section-figure img {
  width: 100%;
  height: auto;
  object-fit: cover;
}

figcaption,
.figure-caption {
  padding: 10px 14px;
  font-size: 13px;
  color: #5b6b7c;
  line-height: 1.6;
  border-top: 1px solid #d8dee5;
  background-color: #ffffff;
}

/* 标签 */

.tag-link {
  display: inline-flex;
  align-items: center;
  min-height: 34px;
  padding: 0 12px;
  font-size: 13px;
  color: #2f6f8f;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

.tag-link:hover,
.tag-link:focus-visible {
  color: #e07a3f;
  border-color: #e07a3f;
}

.change-tag,
.type-tag,
.update-tag {
  display: inline-flex;
  align-items: center;
  padding: 1px 8px;
  font-size: 12px;
  line-height: 1.7;
  border-radius: 3px;
  white-space: nowrap;
}

.change-tag-add,
.type-tag-new {
  color: #2f6f8f;
  background-color: #eaf2f6;
  border: 1px solid #cfe0e9;
}

.change-tag-edit,
.type-tag-adjust {
  color: #e07a3f;
  background-color: #fdf1e8;
  border: 1px solid #f2d6c1;
}

.change-tag-fix,
.type-tag-revise {
  color: #5b6b7c;
  background-color: #f2f4f7;
  border: 1px solid #d8dee5;
}

/* 编号步骤（首页概览 / 观看指南 / 反馈路径共用结构） */

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

.step-item {
  position: relative;
  padding: 18px 18px 18px 60px;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

.step-index {
  position: absolute;
  top: 18px;
  left: 18px;
  width: 28px;
  height: 28px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 600;
  color: #ffffff;
  background-color: #2f6f8f;
  border-radius: 4px;
}

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

.step-text {
  font-size: 14px;
  color: #5b6b7c;
}

/* --------------------------------------------------------------------------
   pages · 首页
   -------------------------------------------------------------------------- */

/* 首屏 */

.hero {
  padding: 40px 0 34px;
}

.hero-inner {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
  gap: 40px;
  align-items: center;
}

.hero-copy {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.hero-eyebrow {
  font-size: 13px;
  color: #e07a3f;
  font-weight: 600;
}

.hero-title {
  font-size: 34px;
  font-weight: 600;
  line-height: 1.35;
  color: #1f2a37;
}

.hero-lead {
  font-size: 15px;
  color: #5b6b7c;
  max-width: 560px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 4px;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 8px;
  padding-top: 18px;
  border-top: 1px solid #d8dee5;
}

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

.content-media-primary {
  margin-top: 34px;
}

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

/* 频道方向总览 */

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

.channel-card {
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  transition: border-color 0.18s ease;
}

.channel-card:hover {
  border-color: #2f6f8f;
}

.channel-name {
  font-size: 17px;
}

.channel-scope {
  font-size: 14px;
  color: #1f2a37;
}

.channel-samples {
  font-size: 13px;
  color: #5b6b7c;
  padding-top: 8px;
  border-top: 1px solid #d8dee5;
}

/* 专题片单摘要 */

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

.topic-card {
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  transition: border-color 0.18s ease;
}

.topic-card:hover {
  border-color: #2f6f8f;
}

.topic-name {
  font-size: 17px;
}

.topic-scope {
  font-size: 14px;
  color: #1f2a37;
}

.topic-meta {
  font-size: 13px;
  color: #5b6b7c;
  padding-top: 8px;
  border-top: 1px solid #d8dee5;
}

/* 变动记录摘要 */

.change-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.change-item {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 10px;
  padding: 12px 16px;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

.change-text {
  flex: 1 1 240px;
  font-size: 14px;
  color: #1f2a37;
}

.change-date {
  font-size: 12px;
  color: #5b6b7c;
}

/* 内容边界与反馈入口 */

.boundary-entry {
  border-top: 1px solid #d8dee5;
}

.boundary-inner {
  display: grid;
  grid-template-columns: minmax(0, 1.6fr) minmax(220px, 1fr);
  gap: 28px;
  align-items: start;
  padding: 26px;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

.boundary-copy {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.boundary-text {
  font-size: 14px;
  color: #5b6b7c;
}

.boundary-actions {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

/* --------------------------------------------------------------------------
   pages · 频道分类页
   -------------------------------------------------------------------------- */

.channel-list .channel-grid {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.channel-list .channel-card {
  padding: 0;
  gap: 0;
  overflow: hidden;
}

.channel-figure {
  border: 0;
  border-bottom: 1px solid #d8dee5;
  border-radius: 0;
}

.channel-figure img {
  aspect-ratio: 16 / 9;
}

.channel-body {
  padding: 16px 18px 18px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.channel-range {
  font-size: 14px;
  color: #1f2a37;
}

.channel-sample {
  font-size: 13px;
  color: #5b6b7c;
}

.channel-type {
  font-size: 13px;
  color: #2f6f8f;
  padding-top: 8px;
  border-top: 1px solid #d8dee5;
}

/* 主栏 + 侧栏 */

.page-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 320px);
  gap: 34px;
  align-items: start;
  margin-top: 8px;
}

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

.page-main .section {
  padding: 26px 0;
}

.page-main .section:first-child {
  padding-top: 0;
}

.page-aside {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.aside-block {
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

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

.aside-text {
  font-size: 13px;
  color: #5b6b7c;
}

.aside-links {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding-top: 10px;
  border-top: 1px solid #d8dee5;
}

.aside-links a {
  font-size: 13px;
  color: #2f6f8f;
  padding: 4px 0;
}

.aside-links a:hover,
.aside-links a:focus-visible {
  color: #e07a3f;
}

/* 字段说明表 */

.field-table {
  font-size: 14px;
  border: 1px solid #d8dee5;
  background-color: #ffffff;
}

.field-caption {
  caption-side: top;
  text-align: left;
  padding: 10px 14px;
  font-size: 13px;
  color: #5b6b7c;
  background-color: #f2f4f7;
  border-bottom: 1px solid #d8dee5;
}

.field-table th,
.field-table td {
  padding: 12px 14px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid #d8dee5;
}

.field-table thead th {
  font-size: 13px;
  font-weight: 600;
  color: #1f2a37;
  background-color: #f2f4f7;
}

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

.field-name {
  width: 26%;
  font-weight: 600;
  color: #1f2a37;
}

/* 频道选择建议 */

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

.tips-item {
  padding: 18px;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

.tips-title {
  font-size: 16px;
  margin-bottom: 8px;
}

.tips-desc {
  font-size: 14px;
  color: #5b6b7c;
}

/* --------------------------------------------------------------------------
   pages · 专题片单页
   -------------------------------------------------------------------------- */

.topic-list {
  padding-bottom: 30px;
  border-bottom: 1px solid #d8dee5;
}

.topic-list .topic-card {
  display: grid;
  grid-template-columns: minmax(0, 260px) minmax(0, 1fr);
  gap: 0;
  padding: 0;
  overflow: hidden;
  margin-bottom: 18px;
}

.topic-list .topic-card:last-child {
  margin-bottom: 0;
}

.topic-figure {
  border: 0;
  border-right: 1px solid #d8dee5;
  border-radius: 0;
  display: flex;
  flex-direction: column;
}

.topic-figure img {
  aspect-ratio: 16 / 10;
  flex: 1 1 auto;
}

.topic-body {
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.topic-meta {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 14px;
  font-size: 13px;
  color: #5b6b7c;
  padding-top: 10px;
  border-top: 1px solid #d8dee5;
}

.topic-meta dt {
  color: #1f2a37;
  font-weight: 600;
}

.topic-meta dd {
  margin: 0;
  color: #5b6b7c;
}

.topic-note {
  font-size: 13px;
  color: #5b6b7c;
}

/* 片单组织方式 */

.organize-notes,
.topic-updates,
.topic-related {
  padding: 30px 0;
  border-bottom: 1px solid #d8dee5;
}

.topic-related {
  border-bottom: 0;
}

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

.organize-item {
  padding: 18px;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

.organize-name {
  font-size: 16px;
  margin-bottom: 8px;
}

.organize-item p {
  font-size: 14px;
  color: #5b6b7c;
}

/* 专题更新摘要 */

.update-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.update-item {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 10px;
  padding: 12px 16px;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

.update-tag {
  color: #2f6f8f;
  background-color: #eaf2f6;
  border: 1px solid #cfe0e9;
}

.update-text {
  flex: 1 1 240px;
  font-size: 14px;
  color: #1f2a37;
}

/* 相关入口 */

.related-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
}

.related-item {
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

.related-item a {
  display: block;
  padding: 16px 18px;
  font-size: 15px;
  font-weight: 600;
  color: #2f6f8f;
}

.related-item a:hover,
.related-item a:focus-visible {
  color: #e07a3f;
}

/* --------------------------------------------------------------------------
   pages · 观看指南页
   -------------------------------------------------------------------------- */

.guide-steps,
.device-notes,
.faq {
  padding: 30px 0;
  border-bottom: 1px solid #d8dee5;
}

.faq {
  border-bottom: 0;
}

.guide-figure {
  margin-bottom: 22px;
}

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

.guide-steps .step-list {
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}

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

.device-card {
  padding: 18px;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

.device-title {
  font-size: 16px;
  margin-bottom: 8px;
}

.device-text {
  font-size: 14px;
  color: #5b6b7c;
}

/* 折叠问答 */

.faq-item {
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
  margin-bottom: 12px;
}

.faq-item:last-of-type {
  margin-bottom: 0;
}

.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  min-height: 52px;
  padding: 12px 18px;
  font-size: 15px;
  font-weight: 600;
  color: #1f2a37;
  cursor: pointer;
  list-style: none;
}

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

.faq-question::after {
  content: "+";
  flex: 0 0 auto;
  font-size: 18px;
  font-weight: 400;
  color: #2f6f8f;
}

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

.faq-item[open] .faq-question {
  color: #2f6f8f;
}

.faq-answer {
  padding: 0 18px 16px;
  font-size: 14px;
  color: #5b6b7c;
  border-top: 1px solid #d8dee5;
  padding-top: 14px;
  margin-top: 0;
}

.faq-footnote {
  margin-top: 18px;
  font-size: 13px;
  color: #5b6b7c;
}

/* --------------------------------------------------------------------------
   pages · 变动记录页
   -------------------------------------------------------------------------- */

.section-type-notes,
.section-change-list,
.section-related-links {
  padding: 30px 0;
}

.section-type-notes {
  padding-top: 4px;
}

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

.type-note {
  padding: 16px 18px;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

.type-note-label {
  margin-bottom: 8px;
}

.type-note-text {
  font-size: 14px;
  color: #5b6b7c;
}

.change-month-group {
  margin-bottom: 26px;
}

.change-month-group:last-of-type {
  margin-bottom: 0;
}

.change-month {
  font-size: 16px;
  color: #1f2a37;
  padding-bottom: 8px;
  margin-bottom: 14px;
  border-bottom: 1px solid #d8dee5;
}

.change-month-group .change-list {
  gap: 10px;
}

.change-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
}

.change-meta time {
  font-size: 12px;
  color: #5b6b7c;
}

.section-figure {
  margin: 26px 0;
}

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

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

.related-link-item {
  padding: 18px;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

.related-link-item a {
  display: inline-block;
  font-size: 15px;
  font-weight: 600;
  color: #2f6f8f;
  margin-bottom: 8px;
}

.related-link-item a:hover,
.related-link-item a:focus-visible {
  color: #e07a3f;
}

.related-link-desc {
  font-size: 13px;
  color: #5b6b7c;
}

/* --------------------------------------------------------------------------
   pages · 内容边界与反馈页
   -------------------------------------------------------------------------- */

.scope-notes,
.boundary-checklist,
.feedback-path {
  padding: 30px 0;
  border-bottom: 1px solid #d8dee5;
}

.scope-notes {
  padding-top: 4px;
}

.feedback-path {
  border-bottom: 0;
}

.scope-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 18px;
  margin-bottom: 26px;
}

.scope-card {
  padding: 18px;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-top-width: 3px;
  border-radius: 4px;
}

.scope-card--in {
  border-top-color: #2f6f8f;
}

.scope-card--out {
  border-top-color: #e07a3f;
}

.scope-card--edge {
  border-top-color: #5b6b7c;
}

.scope-card-title {
  font-size: 16px;
  margin-bottom: 8px;
}

.scope-card-text {
  font-size: 14px;
  color: #5b6b7c;
  margin-bottom: 10px;
}

.scope-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding-top: 10px;
  border-top: 1px solid #d8dee5;
}

.scope-list li {
  position: relative;
  padding-left: 14px;
  font-size: 13px;
  color: #1f2a37;
}

.scope-list li::before {
  content: "";
  position: absolute;
  top: 10px;
  left: 0;
  width: 5px;
  height: 5px;
  background-color: #2f6f8f;
  border-radius: 1px;
}

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

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

.checklist-item {
  position: relative;
  padding: 18px 18px 18px 60px;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
  counter-increment: checklist;
}

.checklist-item::before {
  content: counter(checklist, decimal-leading-zero);
  position: absolute;
  top: 18px;
  left: 18px;
  width: 28px;
  height: 28px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: "SFMono-Regular", "JetBrains Mono", Menlo, Consolas, "Courier New", monospace;
  font-size: 12px;
  font-weight: 600;
  color: #ffffff;
  background-color: #2f6f8f;
  border-radius: 4px;
}

.checklist-title {
  font-size: 16px;
  margin-bottom: 8px;
}

.checklist-text {
  font-size: 14px;
  color: #5b6b7c;
}

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

.feedback-step {
  position: relative;
  padding: 18px 18px 18px 60px;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

.feedback-step .step-index {
  position: absolute;
  top: 18px;
  left: 18px;
  width: 28px;
  height: 28px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 600;
  color: #ffffff;
  background-color: #2f6f8f;
  border-radius: 4px;
}

.feedback-note {
  margin-top: 18px;
  font-size: 13px;
  color: #5b6b7c;
  padding: 14px 18px;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

/* --------------------------------------------------------------------------
   pages · 404
   -------------------------------------------------------------------------- */

.error-main {
  max-width: 1120px;
  margin: 0 auto;
  padding: 60px 24px 40px;
}

.error-inner {
  max-width: 620px;
  margin: 0 auto;
  padding: 34px 28px;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
  text-align: center;
}

.error-code {
  font-size: 44px;
  font-weight: 600;
  color: #2f6f8f;
  line-height: 1.1;
  margin-bottom: 8px;
}

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

.error-desc {
  font-size: 14px;
  color: #5b6b7c;
  margin-bottom: 22px;
}

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

.error-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 20px;
  font-size: 15px;
  font-weight: 600;
  color: #2f6f8f;
  background-color: #ffffff;
  border: 1px solid #d8dee5;
  border-radius: 4px;
}

.error-btn:hover,
.error-btn:focus-visible {
  color: #e07a3f;
  border-color: #e07a3f;
}

.error-note {
  margin-top: 22px;
  font-size: 13px;
  color: #5b6b7c;
}

/* --------------------------------------------------------------------------
   responsive · 960px 与 640px 两档断点
   -------------------------------------------------------------------------- */

@media (max-width: 960px) {
  .header-inner {
    flex-wrap: wrap;
    padding: 0 20px;
  }

  .nav-toggle {
    display: flex;
  }

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

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.24s ease;
  }

  .nav-list.is-open {
    max-height: 420px;
    padding-bottom: 10px;
  }

  .nav-link {
    justify-content: flex-start;
    border-bottom: 1px solid #d8dee5;
    border-left: 2px solid transparent;
    padding: 0 10px;
  }

  .nav-link.is-current {
    border-bottom-color: #d8dee5;
    border-left-color: #2f6f8f;
  }

  .home-main,
  .inner-main {
    padding: 0 20px;
  }

  .inner-main {
    padding-bottom: 44px;
  }

  .hero {
    padding: 30px 0 26px;
  }

  .hero-inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 26px;
  }

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

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

  .page-aside {
    order: 2;
  }

  .footer-inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 24px;
    padding: 34px 20px 24px;
  }

  .footer-copy {
    padding: 16px 20px 26px;
  }

  .boundary-inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 20px;
  }

  .boundary-actions {
    flex-direction: row;
    flex-wrap: wrap;
  }

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

  .topic-figure {
    border-right: 0;
    border-bottom: 1px solid #d8dee5;
  }

  .topic-figure img {
    aspect-ratio: 16 / 9;
  }
}

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

  .header-inner {
    padding: 0 16px;
    min-height: 60px;
  }

  .brand-name {
    font-size: 17px;
  }

  .brand-slogan {
    font-size: 11px;
  }

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

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

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

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

  .page-header {
    padding-bottom: 16px;
    margin-bottom: 20px;
  }

  .hero {
    padding: 24px 0 20px;
  }

  .hero-title {
    font-size: 23px;
  }

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

  .hero-actions .btn {
    flex: 1 1 auto;
  }

  .content-media-primary {
    margin-top: 24px;
  }

  .section {
    padding: 26px 0;
  }

  .section-title {
    font-size: 18px;
  }

  .channel-grid,
  .topic-grid,
  .tips-list,
  .organize-grid,
  .device-grid,
  .related-list,
  .related-link-list,
  .type-note-list,
  .scope-grid,
  .checklist,
  .feedback-steps,
  .step-list,
  .guide-steps .step-list {
    grid-template-columns: minmax(0, 1fr);
  }

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

  .step-item,
  .checklist-item,
  .feedback-step {
    padding: 16px 16px 16px 56px;
  }

  .step-index,
  .checklist-item::before,
  .feedback-step .step-index {
    top: 16px;
    left: 16px;
  }

  .change-item,
  .update-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
  }

  .change-text,
  .update-text {
    flex: 1 1 auto;
  }

  .change-meta {
    flex-wrap: wrap;
  }

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

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

  .field-name {
    width: 34%;
  }

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

  .topic-meta dd {
    margin-bottom: 8px;
  }

  .faq-question {
    font-size: 14px;
    padding: 12px 16px;
  }

  .faq-answer {
    padding: 14px 16px 16px;
  }

  .boundary-inner {
    padding: 20px 16px;
  }

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

  .footer-inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 22px;
    padding: 30px 16px 22px;
  }

  .footer-copy {
    padding: 14px 16px 24px;
  }

  .error-main {
    padding: 40px 16px 30px;
  }

  .error-inner {
    padding: 26px 18px;
  }

  .error-code {
    font-size: 36px;
  }

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

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

  .error-btn {
    width: 100%;
  }
}