:root {
  --ink: #111111;
  --ink-soft: #1a1a1a;
  --muted: #5c5c5c;
  --accent: #e03a3a;
  --surface: #ffffff;
  --surface-alt: #f4f4f4;
  --line: #e2e2e2;
  --line-strong: #cfcfcf;
  --radius: 6px;
  --container: 1120px;
  --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans CJK SC", sans-serif;
  --font-mono: "SFMono-Regular", "Menlo", "Consolas", "Courier New", monospace;
}

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

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

body.site-body {
  margin: 0;
  padding: 0;
  background: var(--surface);
  color: var(--ink-soft);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
}

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

p {
  margin: 0;
}

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

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

a:hover,
a:focus-visible {
  text-decoration: underline;
}

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

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

figure {
  margin: 0;
}

figcaption {
  margin-top: 8px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.6;
}

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

th,
td {
  text-align: left;
  vertical-align: top;
}

time,
.field-table td:first-child {
  font-variant-numeric: tabular-nums;
}

strong {
  font-weight: 700;
}

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

/* ==========================================================================
   layout · 全站骨架
   ========================================================================== */

.site-header {
  background: var(--ink);
  color: #ffffff;
}

.header-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: #ffffff;
  font-size: 19px;
  font-weight: 700;
  letter-spacing: 0;
  white-space: nowrap;
}

.brand:hover,
.brand:focus-visible {
  color: #ffffff;
  text-decoration: none;
}

.site-nav {
  display: block;
}

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

.nav-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 14px;
  color: #f0f0f0;
  font-size: 15px;
  border-bottom: 2px solid transparent;
}

.nav-link:hover,
.nav-link:focus-visible {
  color: #ffffff;
  text-decoration: none;
  border-bottom-color: #7a7a7a;
}

.nav-link.is-current {
  color: #ffffff;
  border-bottom-color: var(--accent);
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  background: transparent;
  border: 1px solid #3a3a3a;
  border-radius: var(--radius);
  cursor: pointer;
}

.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  margin: 4px auto;
  background: #ffffff;
}

.site-main {
  display: block;
}

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

.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 16px;
  color: var(--muted);
  font-size: 14px;
}

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

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

.page-header {
  padding-bottom: 18px;
  margin-bottom: 28px;
  border-bottom: 1px solid var(--line);
}

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

.page-description {
  margin-top: 10px;
  max-width: 760px;
  color: var(--muted);
  font-size: 15px;
}

.page-layout {
  display: grid;
  gap: 40px;
}

.page-layout.sidebar-left {
  grid-template-columns: 240px minmax(0, 1fr);
}

.page-layout.layout-shell {
  grid-template-columns: minmax(0, 1fr) 300px;
}

.layout-content,
.content-column,
.page-content {
  min-width: 0;
}

.site-footer {
  background: var(--surface-alt);
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
}

.footer-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 40px 24px 24px;
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  gap: 40px;
}

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

.footer-brand-desc {
  margin-top: 8px;
  color: var(--muted);
  font-size: 14px;
}

.footer-nav {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 24px;
}

.footer-group-title {
  font-size: 15px;
  font-weight: 700;
  margin-bottom: 10px;
}

.footer-group-title a {
  color: var(--ink);
}

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

.footer-list a {
  color: var(--muted);
  font-size: 14px;
}

.footer-list a:hover,
.footer-list a:focus-visible {
  color: var(--accent);
}

.footer-bottom {
  max-width: var(--container);
  margin: 0 auto;
  padding: 16px 24px 32px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 13px;
}

.footer-note {
  margin-bottom: 6px;
}

/* ==========================================================================
   components · 通用组件
   ========================================================================== */

.section {
  margin-bottom: 56px;
}

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

.section-title {
  font-size: 22px;
  font-weight: 700;
  color: var(--ink);
}

.section-desc {
  margin-top: 8px;
  max-width: 780px;
  color: var(--muted);
  font-size: 15px;
}

.section-lead,
.section-intro {
  margin-bottom: 20px;
  max-width: 780px;
  color: var(--muted);
  font-size: 15px;
}

.sub-title {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 12px;
}

.section-foot {
  margin-top: 20px;
  color: var(--muted);
  font-size: 14px;
}

.section-note {
  margin-top: 16px;
  color: var(--muted);
  font-size: 14px;
}

.text-link {
  color: var(--accent);
  font-size: 14px;
}

.field-table {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  font-size: 14px;
}

.field-table caption,
.table-caption,
.field-table-caption {
  padding: 10px 14px;
  background: var(--surface-alt);
  color: var(--muted);
  font-size: 13px;
  text-align: left;
  caption-side: top;
}

.field-table th,
.field-table td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--line);
  line-height: 1.7;
}

.field-table thead th {
  background: var(--surface-alt);
  font-size: 13px;
  font-weight: 700;
  color: var(--ink);
}

.field-table tbody tr:nth-child(even) {
  background: #fafafa;
}

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

.field-table td:first-child {
  width: 120px;
  font-weight: 700;
  color: var(--ink);
}

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

.video-card-list {
  display: grid;
  gap: 12px;
}

.video-card {
  min-width: 0;
}

.video-card-link {
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  grid-template-rows: auto auto;
  gap: 2px 12px;
  align-items: center;
  padding: 8px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--ink);
}

.video-card-link:hover,
.video-card-link:focus-visible {
  text-decoration: none;
  border-color: var(--accent);
}

.video-card-link img {
  grid-row: 1 / 3;
  width: 96px;
  height: 58px;
  object-fit: cover;
  border-radius: 4px;
  background: var(--surface-alt);
}

.video-card-name {
  font-size: 15px;
  font-weight: 700;
  line-height: 1.4;
}

.video-card-meta {
  color: var(--muted);
  font-size: 13px;
}

.channel-samples {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.channel-samples .video-card {
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.channel-samples .video-card img {
  width: 100%;
  height: 132px;
  object-fit: cover;
  border-radius: 4px;
  background: var(--surface-alt);
}

.topic-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
}

.topic-card {
  min-width: 0;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.topic-card img,
.topic-figure img {
  width: 100%;
  height: 168px;
  object-fit: cover;
  border-radius: 4px;
  background: var(--surface-alt);
}

.topic-name {
  margin-top: 12px;
  font-size: 17px;
}

.topic-desc,
.topic-angle {
  margin-top: 8px;
  color: var(--muted);
  font-size: 14px;
}

.topic-count,
.topic-meta {
  margin-top: 8px;
  color: var(--ink);
  font-size: 13px;
  font-weight: 700;
}

.channel-tree,
.topic-tree {
  align-self: start;
  padding: 18px;
  background: var(--surface-alt);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.sidebar-title,
.tree-title {
  font-size: 16px;
  font-weight: 700;
  padding-bottom: 10px;
  margin-bottom: 12px;
  border-bottom: 1px solid var(--line-strong);
}

.tree-group + .tree-group {
  margin-top: 18px;
}

.tree-group-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: 8px;
}

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

.tree-link {
  display: block;
  min-height: 44px;
  padding: 10px 10px;
  border-radius: 4px;
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1.5;
}

.tree-link:hover,
.tree-link:focus-visible {
  background: #eaeaea;
  text-decoration: none;
}

.tree-link.is-current {
  color: var(--accent);
  font-weight: 700;
  background: #ffffff;
}

.page-aside {
  align-self: start;
  position: sticky;
  top: 24px;
  padding: 18px;
  background: var(--surface-alt);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.aside-title {
  font-size: 15px;
  font-weight: 700;
  padding-bottom: 10px;
  margin-bottom: 12px;
  border-bottom: 1px solid var(--line-strong);
}

.toc-item + .toc-item {
  margin-top: 2px;
}

.toc-link {
  display: block;
  min-height: 44px;
  padding: 10px;
  border-radius: 4px;
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1.5;
}

.toc-link:hover,
.toc-link:focus-visible {
  background: #eaeaea;
  text-decoration: none;
}

.toc-link.is-active {
  color: var(--accent);
  font-weight: 700;
  background: #ffffff;
}

.aside-note {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--line-strong);
  color: var(--muted);
  font-size: 13px;
}

.step-list {
  counter-reset: step;
  display: grid;
  gap: 16px;
}

.step-item {
  padding: 16px 18px;
  border-left: 3px solid var(--accent);
  background: var(--surface-alt);
  border-radius: 0 var(--radius) var(--radius) 0;
}

.step-title {
  font-size: 17px;
  margin-bottom: 6px;
}

.step-text {
  color: var(--ink-soft);
  font-size: 15px;
}

.step-link {
  margin-top: 8px;
  font-size: 14px;
}

.faq-list {
  display: grid;
  gap: 10px;
}

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

.faq-question {
  padding: 14px 16px;
  min-height: 44px;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
  cursor: pointer;
  list-style: none;
}

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

.faq-question::after {
  content: "＋";
  float: right;
  color: var(--accent);
  font-weight: 700;
}

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

.faq-answer {
  padding: 0 16px 16px;
  color: var(--muted);
  font-size: 15px;
}

.next-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.next-item {
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.next-title {
  font-size: 16px;
  margin-bottom: 6px;
}

.next-text {
  color: var(--muted);
  font-size: 14px;
}

/* ==========================================================================
   pages · 首页
   ========================================================================== */

.topbar {
  background: var(--surface-alt);
  border-bottom: 1px solid var(--line);
}

.topbar p {
  max-width: var(--container);
  margin: 0 auto;
  padding: 8px 24px;
  color: var(--muted);
  font-size: 13px;
}

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

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  gap: 40px;
  margin-bottom: 64px;
}

.hero-intro {
  min-width: 0;
}

.hero-title {
  font-size: 32px;
  font-weight: 700;
  color: var(--ink);
}

.hero-desc {
  margin-top: 12px;
  max-width: 560px;
  color: var(--muted);
  font-size: 16px;
}

.hero-media {
  margin-top: 22px;
}

.hero-media img {
  width: 100%;
  height: 260px;
  object-fit: cover;
  border-radius: var(--radius);
  background: var(--surface-alt);
}

.hero-panel {
  min-width: 0;
  padding: 20px;
  background: var(--surface-alt);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.hero-panel-title {
  font-size: 17px;
  margin-bottom: 12px;
}

.use-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 18px;
}

.use-tag {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 14px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: var(--surface);
  color: var(--ink);
  font-size: 14px;
}

.use-tag:hover,
.use-tag:focus-visible {
  border-color: var(--accent);
  color: var(--accent);
  text-decoration: none;
}

.hero-panel-note {
  margin-top: 14px;
  font-size: 13px;
  color: var(--muted);
}

.channel-row-list {
  border-top: 1px solid var(--line);
}

.channel-row {
  display: grid;
  grid-template-columns: 180px minmax(0, 1fr);
  gap: 6px 24px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.channel-row .channel-name {
  grid-row: 1 / 4;
  font-size: 17px;
}

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

.channel-row .channel-name a:hover,
.channel-row .channel-name a:focus-visible {
  color: var(--accent);
  text-decoration: none;
}

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

.channel-field a {
  font-size: 14px;
}

.log-groups {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 24px;
}

.log-month {
  padding: 18px;
  background: var(--surface-alt);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.log-month-title {
  font-size: 16px;
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--line-strong);
}

.log-item {
  padding: 10px 0;
  border-bottom: 1px dashed var(--line-strong);
}

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

.log-date {
  display: inline-block;
  color: var(--accent);
  font-size: 13px;
  font-weight: 700;
}

.log-target {
  display: inline-block;
  margin-left: 8px;
  color: var(--ink);
  font-size: 13px;
  font-weight: 700;
}

.log-text {
  margin-top: 4px;
  color: var(--muted);
  font-size: 14px;
}

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

.guide-summary-col {
  min-width: 0;
}

.guide-summary-col .step-list {
  gap: 10px;
}

.guide-summary-col .step-item {
  padding: 12px 14px;
}

.index-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 20px;
}

.index-col {
  min-width: 0;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

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

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

.index-name a:hover,
.index-name a:focus-visible {
  color: var(--accent);
  text-decoration: none;
}

.index-desc {
  color: var(--muted);
  font-size: 14px;
}

/* ==========================================================================
   pages · 频道分类
   ========================================================================== */

.channel-overview .overview-media {
  margin-bottom: 22px;
}

.overview-media img {
  width: 100%;
  height: 240px;
  object-fit: cover;
  border-radius: var(--radius);
  background: var(--surface-alt);
}

.channel-table {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-size: 14px;
  min-width: 640px;
}

.channel-table caption {
  padding: 10px 14px;
  background: var(--surface-alt);
  color: var(--muted);
  font-size: 13px;
  text-align: left;
}

.channel-table th,
.channel-table td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--line);
  line-height: 1.7;
}

.channel-table thead th {
  background: var(--surface-alt);
  font-size: 13px;
  font-weight: 700;
  color: var(--ink);
}

.channel-table tbody tr:nth-child(even) {
  background: #fafafa;
}

.channel-table tbody tr:last-child td {
  border-bottom: 0;
}

.channel-table td:first-child {
  font-weight: 700;
  color: var(--ink);
  white-space: nowrap;
}

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

.channel-block .channel-name {
  font-size: 18px;
  margin-bottom: 10px;
}

.channel-desc {
  color: var(--ink-soft);
  font-size: 15px;
}

.channel-sort {
  margin-top: 12px;
  display: grid;
  gap: 6px;
}

.channel-sort li {
  position: relative;
  padding-left: 16px;
  color: var(--muted);
  font-size: 14px;
}

.channel-sort li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 11px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
}

.channel-samples {
  margin-top: 16px;
}

.choice-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

.choice-item {
  min-width: 0;
  padding: 18px;
  background: var(--surface-alt);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

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

.choice-desc {
  color: var(--muted);
  font-size: 14px;
}

.choice-links {
  margin-top: 10px;
  font-size: 14px;
}

/* ==========================================================================
   pages · 专题片单
   ========================================================================== */

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

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

.order-name {
  font-size: 18px;
  margin-bottom: 10px;
}

.order-desc {
  color: var(--ink-soft);
  font-size: 15px;
}

.order-list {
  margin-top: 12px;
  display: grid;
  gap: 6px;
}

.order-list li {
  position: relative;
  padding-left: 16px;
  color: var(--muted);
  font-size: 14px;
}

.order-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 11px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
}

.order-entries {
  margin-top: 16px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.entry-card {
  min-width: 0;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface-alt);
}

.entry-name {
  font-size: 15px;
  margin-bottom: 8px;
}

.entry-fields {
  color: var(--muted);
  font-size: 13px;
  line-height: 1.9;
}

.mapping-table td:first-child {
  white-space: nowrap;
}

/* ==========================================================================
   pages · 观看指南
   ========================================================================== */

.guide-section {
  padding-bottom: 32px;
  margin-bottom: 32px;
  border-bottom: 1px solid var(--line);
}

.guide-section:last-child {
  border-bottom: 0;
  margin-bottom: 0;
}

.guide-figure {
  margin: 18px 0 22px;
}

.guide-figure img {
  width: 100%;
  height: 260px;
  object-fit: cover;
  border-radius: var(--radius);
  background: var(--surface-alt);
}

.field-note {
  margin-top: 12px;
  color: var(--muted);
  font-size: 14px;
}

/* ==========================================================================
   pages · 关于本站
   ========================================================================== */

.content-section {
  padding-bottom: 32px;
  margin-bottom: 32px;
  border-bottom: 1px solid var(--line);
}

.content-section:last-child {
  border-bottom: 0;
  margin-bottom: 0;
}

.content-section p + p {
  margin-top: 12px;
}

.content-section p {
  color: var(--ink-soft);
}

.audience-list {
  margin-top: 14px;
  display: grid;
  gap: 8px;
}

.audience-list li {
  position: relative;
  padding-left: 16px;
  color: var(--muted);
  font-size: 15px;
}

.audience-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 11px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
}

.content-figure {
  margin-top: 22px;
}

.content-figure img {
  width: 100%;
  height: 240px;
  object-fit: cover;
  border-radius: var(--radius);
  background: var(--surface-alt);
}

.principle-columns {
  margin-top: 18px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

.principle-item {
  min-width: 0;
  padding: 18px;
  background: var(--surface-alt);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

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

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

.principle-item .text-link {
  display: inline-block;
  margin-top: 10px;
}

.boundary-list {
  margin-top: 16px;
  display: grid;
  gap: 14px;
}

.boundary-item {
  padding: 16px 18px;
  border-left: 3px solid var(--accent);
  background: var(--surface-alt);
  border-radius: 0 var(--radius) var(--radius) 0;
}

.boundary-name {
  font-size: 16px;
  margin-bottom: 6px;
}

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

.path-list {
  margin-top: 16px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

.path-item {
  min-width: 0;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

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

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

.path-item .text-link {
  display: inline-block;
  margin-top: 10px;
}

/* ==========================================================================
   pages · 404
   ========================================================================== */

.error-main {
  max-width: var(--container);
  margin: 0 auto;
  padding: 64px 24px 80px;
}

.error-panel {
  max-width: 640px;
}

.error-code {
  font-family: var(--font-mono);
  color: var(--accent);
  font-size: 14px;
  font-weight: 700;
}

.error-title {
  margin-top: 8px;
  font-size: 32px;
}

.error-desc {
  margin-top: 12px;
  color: var(--muted);
  font-size: 16px;
}

.error-list {
  margin-top: 20px;
  display: grid;
  gap: 8px;
}

.error-list li {
  position: relative;
  padding-left: 16px;
  color: var(--ink-soft);
  font-size: 15px;
}

.error-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 11px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
}

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

.btn-primary,
.btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 20px;
  border-radius: var(--radius);
  font-size: 15px;
}

.btn-primary {
  background: var(--accent);
  color: #ffffff;
  border: 1px solid var(--accent);
}

.btn-primary:hover,
.btn-primary:focus-visible {
  text-decoration: none;
  background: #c22f2f;
  border-color: #c22f2f;
}

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

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

/* ==========================================================================
   responsive
   ========================================================================== */

@media (max-width: 1024px) {
  .page-layout.sidebar-left {
    grid-template-columns: 210px minmax(0, 1fr);
  }

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

  .footer-inner {
    grid-template-columns: 220px minmax(0, 1fr);
  }

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

@media (max-width: 768px) {
  .header-inner {
    padding: 0 16px;
    min-height: 60px;
    flex-wrap: wrap;
  }

  .nav-toggle {
    display: block;
  }

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

  .nav-list {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding-bottom: 10px;
  }

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

  .nav-link {
    justify-content: flex-start;
    padding: 0 4px;
    border-bottom: 1px solid #2c2c2c;
  }

  .nav-link.is-current {
    border-bottom-color: var(--accent);
  }

  .inner-main,
  .home-main,
  .error-main {
    padding-left: 16px;
    padding-right: 16px;
  }

  .topbar p {
    padding-left: 16px;
    padding-right: 16px;
  }

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

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

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

  .page-aside {
    position: static;
    top: auto;
  }

  .hero {
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
    margin-bottom: 48px;
  }

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

  .channel-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 6px;
  }

  .channel-row .channel-name {
    grid-row: auto;
  }

  .topic-grid,
  .topic-overview .topic-grid,
  .guide-summary-columns,
  .channel-samples,
  .order-entries,
  .next-list,
  .choice-list,
  .principle-columns,
  .path-list,
  .log-groups {
    grid-template-columns: minmax(0, 1fr);
  }

  .footer-inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
    padding: 32px 16px 20px;
  }

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

  .footer-bottom {
    padding: 14px 16px 28px;
  }

  .overview-media img,
  .guide-figure img,
  .content-figure img {
    height: 200px;
  }
}

@media (max-width: 480px) {
  .index-grid,
  .footer-nav {
    grid-template-columns: minmax(0, 1fr);
  }

  .video-card-link {
    grid-template-columns: 84px minmax(0, 1fr);
  }

  .video-card-link img {
    width: 84px;
    height: 52px;
  }

  .hero-media img {
    height: 190px;
  }

  .topic-card img,
  .topic-figure img {
    height: 150px;
  }

  .channel-samples .video-card img {
    height: 160px;
  }

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