:root {
  --canvas: #faf8f4;
  --surface: #ffffff;
  --ink: #1f2328;
  --ink-soft: #5c6169;
  --rule: #dcd6c8;
  --accent: #b4451f;
  --indigo: #2a3f6b;
  --wash: #f2ede3;
  --font-body: system-ui, -apple-system, "Segoe UI", "Noto Sans SC", sans-serif;
  --font-mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  --shell: 1180px;
  --read: 720px;
  --pad: 24px;
}

/* ============================================================
   base
   ============================================================ */

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

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

body {
  margin: 0;
  background: var(--canvas);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--ink);
  text-decoration: underline;
  text-decoration-color: rgba(92, 97, 105, 0.45);
  text-underline-offset: 3px;
}

a:hover,
a:focus-visible {
  color: var(--accent);
  text-decoration-color: var(--accent);
}

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

h1 {
  font-size: clamp(26px, 3.4vw, 38px);
  font-weight: 700;
}

h2 {
  font-size: 24px;
}

h3 {
  font-size: 18px;
}

p {
  margin: 0 0 18px;
}

p:last-child {
  margin-bottom: 0;
}

ul,
ol {
  margin: 0 0 18px;
  padding-left: 1.25em;
}

ul:last-child,
ol:last-child {
  margin-bottom: 0;
}

li {
  margin-bottom: 8px;
}

li:last-child {
  margin-bottom: 0;
}

dl,
dd {
  margin: 0;
}

figure {
  margin: 0;
}

figcaption {
  margin-top: 8px;
  font-size: 13px;
  color: var(--ink-soft);
  font-family: var(--font-mono);
  letter-spacing: 0.02em;
  line-height: 1.6;
}

code {
  font-family: var(--font-mono);
  font-size: 0.94em;
}

button {
  font: inherit;
  color: inherit;
}

.mono {
  font-family: var(--font-mono);
  letter-spacing: 0.02em;
}

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

.skip-link {
  position: absolute;
  left: 12px;
  top: -60px;
  z-index: 60;
  padding: 10px 16px;
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 3px;
  font-size: 14px;
  text-decoration: none;
}

.skip-link:focus {
  top: 12px;
}

/* ============================================================
   layout — shell / header / nav / footer
   ============================================================ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--canvas);
  border-bottom: 1px solid var(--rule);
}

.header-inner {
  width: 100%;
  max-width: var(--shell);
  margin: 0 auto;
  padding: 16px var(--pad);
  display: flex;
  align-items: center;
  gap: 28px;
}

.brand {
  flex: 0 0 auto;
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
  text-decoration: none;
  white-space: nowrap;
}

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

.site-nav {
  flex: 1 1 auto;
  display: flex;
  align-items: flex-start;
  gap: 26px;
  min-width: 0;
}

.nav-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

.nav-group-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--ink-soft);
  text-transform: uppercase;
}

.nav-list {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav-list li {
  margin: 0;
}

.nav-link {
  display: inline-block;
  padding: 3px 2px;
  font-size: 14px;
  color: var(--ink);
  text-decoration: none;
  border-left: 2px solid transparent;
  padding-left: 8px;
}

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

.nav-link.is-current {
  color: var(--accent);
  border-left-color: var(--accent);
  font-weight: 600;
}

.menu-toggle {
  flex: 0 0 auto;
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 3px;
  cursor: pointer;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
}

.menu-toggle-bar {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--ink);
}

.mobile-drawer {
  border-top: 1px solid var(--rule);
  background: var(--surface);
}

.mobile-drawer[hidden] {
  display: none;
}

.drawer-nav {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 12px var(--pad) 20px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.drawer-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.drawer-group-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--ink-soft);
}

.drawer-group ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.drawer-group li {
  margin: 0;
}

.drawer-link {
  display: flex;
  align-items: center;
  min-height: 48px;
  padding: 0 10px;
  font-size: 15px;
  color: var(--ink);
  text-decoration: none;
  border-left: 2px solid transparent;
  border-bottom: 1px solid var(--rule);
}

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

.drawer-link.is-current {
  color: var(--accent);
  border-left-color: var(--accent);
  font-weight: 600;
}

.site-main {
  display: block;
}

.home-main {
  width: 100%;
  max-width: var(--shell);
  margin: 0 auto;
  padding: 0 var(--pad) 56px;
}

.site-footer {
  border-top: 1px solid var(--rule);
  background: var(--canvas);
}

.footer-inner {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 22px var(--pad);
  display: flex;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
}

.footer-brand {
  flex: 1 1 220px;
  min-width: 0;
}

.footer-brand-name {
  display: block;
  font-size: 14px;
  font-weight: 700;
  color: var(--ink);
}

.footer-brand-desc {
  margin: 2px 0 0;
  font-size: 13px;
  color: var(--ink-soft);
  line-height: 1.6;
}

.footer-links {
  flex: 0 0 auto;
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
}

.footer-links a {
  font-size: 14px;
  color: var(--ink-soft);
  text-decoration: none;
}

.footer-links a:hover,
.footer-links a:focus-visible {
  color: var(--accent);
  text-decoration: underline;
}

.footer-copy {
  flex: 0 0 auto;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--ink-soft);
}

/* ============================================================
   layout — inner page shell (breadcrumb / title / columns)
   ============================================================ */

.breadcrumb {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 18px var(--pad) 0;
  font-size: 13px;
  color: var(--ink-soft);
}

.inner-main > .breadcrumb {
  max-width: none;
  margin: 0;
  padding: 0 0 14px;
}

.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.breadcrumb-item {
  margin: 0;
  font-size: 13px;
  color: var(--ink-soft);
}

.breadcrumb-item a {
  color: var(--ink-soft);
  text-decoration: none;
}

.breadcrumb-item a:hover,
.breadcrumb-item a:focus-visible {
  color: var(--accent);
  text-decoration: underline;
}

.breadcrumb-item + .breadcrumb-item::before {
  content: "/";
  margin-right: 6px;
  color: var(--rule);
}

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

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

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

.page-layout {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 18px var(--pad) 56px;
  display: grid;
  grid-template-columns: 210px minmax(0, 1fr) 200px;
  gap: 48px;
  align-items: start;
}

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

.page-header {
  margin: 0 0 10px;
}

.page-title {
  margin: 0;
  font-size: clamp(26px, 3.4vw, 38px);
  font-weight: 700;
  color: var(--ink);
  line-height: 1.3;
}

.page-title .page-lead,
.page-title .page-lede {
  margin: 12px 0 0;
  font-size: 16px;
  color: var(--ink-soft);
  line-height: 1.7;
}

.page-title .page-meta {
  margin: 10px 0 0;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.02em;
  color: var(--ink-soft);
}

.page-lead,
.page-lede {
  margin: 12px 0 0;
  font-size: 16px;
  color: var(--ink-soft);
  line-height: 1.7;
}

.page-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 10px 0 0;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.02em;
  color: var(--ink-soft);
}

.meta-mono {
  font-family: var(--font-mono);
  letter-spacing: 0.02em;
}

.meta-sep {
  color: var(--rule);
}

.meta-line {
  margin: 14px 0 0;
  font-size: 13px;
  color: var(--ink-soft);
}

/* ============================================================
   components — shared document blocks
   ============================================================ */

.content-section,
.doc-section,
.section {
  padding: 28px 0;
  border-top: 1px solid var(--rule);
}

.content-section:first-of-type,
.doc-section:first-of-type,
.section:first-of-type {
  border-top: 0;
  padding-top: 20px;
}

.content-section > h2,
.doc-section > h2,
.section > h2 {
  margin: 0 0 12px;
  font-size: 24px;
  padding-left: 0;
  position: relative;
}

.content-section > h2::before,
.doc-section > h2::before,
.section > h2::before {
  content: "";
  display: block;
  width: 24px;
  height: 2px;
  background: var(--accent);
  margin-bottom: 8px;
}

.section-lead,
.section-intro {
  margin: 0 0 18px;
  color: var(--ink-soft);
  font-size: 15px;
}

.section-note {
  margin: 16px 0 0;
  font-size: 14px;
  color: var(--ink-soft);
}

.section-links {
  margin: 16px 0 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
}

.inline-link {
  font-size: 14px;
  color: var(--indigo);
}

.inline-link:hover,
.inline-link:focus-visible {
  color: var(--accent);
}

.notice {
  margin: 18px 0 0;
  padding: 12px 14px;
  background: var(--wash);
  border-left: 3px solid var(--indigo);
  border-radius: 2px;
  font-size: 14px;
  color: var(--ink);
  line-height: 1.7;
}

.notice p {
  margin: 0;
}

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

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

.plain-list {
  margin: 0 0 6px;
  padding-left: 1.2em;
}

.plain-list li {
  margin-bottom: 8px;
}

.point-list {
  margin: 0;
  padding-left: 1.2em;
}

.point-list li {
  margin-bottom: 10px;
}

.media-figure,
.content-figure,
.selfcheck-figure,
.materials-figure {
  margin: 20px 0 0;
  border: 1px solid var(--rule);
  border-radius: 3px;
  background: var(--surface);
  overflow: hidden;
}

.media-figure img,
.content-figure img,
.selfcheck-figure img,
.materials-figure img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  background: var(--wash);
}

.media-figure figcaption,
.content-figure figcaption,
.selfcheck-figure figcaption,
.materials-figure figcaption {
  margin: 0;
  padding: 10px 12px;
  border-top: 1px solid var(--rule);
  font-size: 12px;
  color: var(--ink-soft);
}

/* step list — shared baseline, scoped per parent */

.step-list {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: step;
}

.step-item {
  display: flex;
  gap: 12px;
  padding: 12px 0;
  border-top: 1px solid var(--rule);
  margin: 0;
}

.step-item:first-child {
  border-top: 0;
  padding-top: 0;
}

.step-num,
.step-index {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.02em;
  color: var(--indigo);
  padding-top: 2px;
}

.step-body,
.step-content {
  flex: 1 1 auto;
  min-width: 0;
}

.step-body strong {
  display: block;
  font-size: 15px;
  margin-bottom: 2px;
}

.step-title {
  margin: 0 0 4px;
  font-size: 16px;
}

.step-desc {
  margin: 0;
  font-size: 14px;
  color: var(--ink-soft);
  line-height: 1.7;
}

/* ============================================================
   components — sidebars (version rail / toc)
   ============================================================ */

.version-panel,
.aside-version,
.version-rail,
.toc-panel,
.toc-rail,
.page-toc,
.aside-toc {
  position: sticky;
  top: 84px;
  font-size: 13px;
  color: var(--ink-soft);
  align-self: start;
  min-width: 0;
}

.version-panel-label,
.version-rail-label,
.aside-label,
.toc-panel-label,
.toc-label,
.version-panel-title,
.toc-title,
.page-toc .toc-label {
  display: block;
  margin: 0 0 4px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
  font-weight: 400;
}

.version-panel-code,
.version-rail-code,
.version-rail-value,
.aside-mono,
.version-panel .version-panel-code {
  display: block;
  margin: 0 0 16px;
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: 0.02em;
  color: var(--indigo);
  font-weight: 600;
  line-height: 1.4;
}

.version-panel-links,
.version-rail-links,
.rail-links,
.aside-link-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.version-panel-links li,
.version-rail-links li,
.rail-links li,
.aside-link-list li {
  margin: 0 0 6px;
}

.version-panel-links a,
.version-rail-links a,
.rail-links a,
.aside-link-list a {
  display: block;
  padding: 4px 0;
  font-size: 13px;
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--rule);
}

.version-panel-links a:hover,
.version-rail-links a:hover,
.rail-links a:hover,
.aside-link-list a:hover,
.version-panel-links a:focus-visible,
.version-rail-links a:focus-visible,
.rail-links a:focus-visible,
.aside-link-list a:focus-visible {
  color: var(--accent);
}

.version-panel-note,
.version-rail-note,
.rail-note {
  margin: 12px 0 0;
  font-size: 12px;
  color: var(--ink-soft);
  line-height: 1.6;
}

.aside-block {
  margin-bottom: 16px;
}

.aside-block:last-child {
  margin-bottom: 0;
}

.version-rail-block {
  margin-bottom: 14px;
}

.version-meta {
  margin: 0 0 12px;
}

.version-meta-row {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  padding: 6px 0;
  border-bottom: 1px solid var(--rule);
  font-size: 12px;
}

.version-meta-row dt {
  color: var(--ink-soft);
}

.version-meta-row dd {
  font-family: var(--font-mono);
  color: var(--indigo);
  text-align: right;
}

.version-rail-inner {
  border: 1px solid var(--rule);
  border-radius: 3px;
  background: var(--surface);
  padding: 14px;
}

.rail-label {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.rail-value {
  margin: 0 0 12px;
  font-size: 14px;
  color: var(--indigo);
  font-weight: 600;
}

.toc-list {
  margin: 0;
  padding: 0;
  list-style: none;
  border-left: 1px solid var(--rule);
}

.toc-item,
.toc-list li {
  margin: 0;
}

.toc-link {
  display: block;
  padding: 5px 0 5px 12px;
  font-size: 13px;
  color: var(--ink-soft);
  text-decoration: none;
  border-left: 2px solid transparent;
  margin-left: -1px;
  line-height: 1.5;
}

.toc-link:hover,
.toc-link:focus-visible {
  color: var(--indigo);
  border-left-color: var(--indigo);
}

.toc-link.is-active {
  color: var(--indigo);
  border-left-color: var(--indigo);
  font-weight: 600;
}

/* ============================================================
   pages — index
   ============================================================ */

.status-strip {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0;
  border-bottom: 1px solid var(--rule);
  margin: 0 calc(var(--pad) * -1);
  padding: 0 var(--pad);
}

.status-cell {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 10px;
  padding: 12px 18px;
  border-left: 1px solid var(--rule);
  min-width: 0;
}

.status-cell:first-child {
  border-left: 0;
  padding-left: 0;
}

.status-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.status-value {
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
  color: var(--indigo);
}

.status-link {
  color: var(--indigo);
  text-decoration: none;
}

.status-link:hover,
.status-link:focus-visible {
  color: var(--accent);
  text-decoration: underline;
}

.status-note {
  font-size: 12px;
  color: var(--ink-soft);
  line-height: 1.5;
}

.hero-split {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
  gap: 40px;
  padding: 36px 0 32px;
  align-items: start;
}

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

.hero-text h1 {
  margin: 0 0 14px;
}

.hero-lead {
  margin: 0 0 20px;
  font-size: 17px;
  color: var(--ink-soft);
  line-height: 1.7;
  max-width: 60ch;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 22px;
}

.btn-primary,
.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 20px;
  border-radius: 3px;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  line-height: 1.4;
}

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

.btn-primary:hover,
.btn-primary:focus-visible {
  background: #993a19;
  color: #fff;
  text-decoration: none;
}

.btn-secondary {
  background: var(--surface);
  color: var(--ink);
  border: 1px solid var(--rule);
}

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

.hero-figure {
  margin: 0;
  border: 1px solid var(--rule);
  border-radius: 3px;
  overflow: hidden;
  background: var(--surface);
}

.hero-figure img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  background: var(--wash);
}

.hero-figure figcaption {
  margin: 0;
  padding: 10px 14px;
  border-top: 1px solid var(--rule);
  font-size: 12px;
  color: var(--ink-soft);
}

.hero-index {
  display: grid;
  grid-template-rows: auto auto auto;
  gap: 12px;
  min-width: 0;
}

.index-card {
  display: grid;
  gap: 4px;
  padding: 14px 16px;
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 3px;
  text-decoration: none;
  color: var(--ink);
  min-height: 44px;
}

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

.index-card:hover .index-title,
.index-card:focus-visible .index-title {
  color: var(--accent);
}

.index-card-featured {
  border-color: var(--indigo);
  background: var(--surface);
  padding: 18px 18px;
}

.index-num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--indigo);
}

.index-title {
  font-size: 16px;
  font-weight: 700;
  line-height: 1.4;
}

.index-card-featured .index-title {
  font-size: 19px;
}

.index-desc {
  font-size: 13px;
  color: var(--ink-soft);
  line-height: 1.6;
}

.conclusion {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
  gap: 40px;
  padding: 32px 0;
  border-top: 1px solid var(--rule);
  align-items: start;
}

.conclusion-text {
  min-width: 0;
}

.conclusion-text h2 {
  margin: 0 0 12px;
}

.conclusion-list {
  margin: 16px 0 0;
  padding-left: 1.2em;
}

.conclusion-list li {
  margin-bottom: 8px;
  font-size: 15px;
  line-height: 1.7;
}

.conclusion-figure {
  margin: 0;
  border: 1px solid var(--rule);
  border-radius: 3px;
  overflow: hidden;
  background: var(--surface);
}

.conclusion-figure img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  background: var(--wash);
}

.conclusion-figure figcaption {
  margin: 0;
  padding: 10px 12px;
  border-top: 1px solid var(--rule);
  font-size: 12px;
  color: var(--ink-soft);
}

.dir-list {
  padding: 32px 0;
  border-top: 1px solid var(--rule);
}

.dir-list h2 {
  margin: 0 0 8px;
}

.dir-list .section-lead {
  margin: 0 0 20px;
}

.dir-rows {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--rule);
}

.dir-row {
  display: grid;
  grid-template-columns: 48px minmax(0, 150px) minmax(0, 1fr) auto;
  gap: 16px;
  align-items: center;
  padding: 16px 0;
  border-bottom: 1px solid var(--rule);
  margin: 0;
}

.dir-num {
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--indigo);
  font-weight: 600;
}

.dir-name {
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
}

.dir-desc {
  font-size: 14px;
  color: var(--ink-soft);
  line-height: 1.65;
  min-width: 0;
}

.dir-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 36px;
  padding: 0 14px;
  font-size: 13px;
  font-family: var(--font-mono);
  color: var(--indigo);
  text-decoration: none;
  border: 1px solid var(--rule);
  border-radius: 3px;
  white-space: nowrap;
}

.dir-link::after {
  content: "→";
  margin-left: 6px;
}

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

.playlist-triplet {
  padding: 32px 0;
  border-top: 1px solid var(--rule);
}

.playlist-triplet h2 {
  margin: 0 0 8px;
}

.playlist-triplet .section-lead {
  margin: 0 0 22px;
}

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

.playlist-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 0 0 16px;
  border: 1px solid var(--rule);
  border-radius: 3px;
  background: var(--surface);
  min-width: 0;
  overflow: hidden;
}

.playlist-figure {
  margin: 0;
}

.playlist-figure img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  background: var(--wash);
}

.playlist-card h3 {
  margin: 0;
  padding: 0 16px;
  font-size: 17px;
}

.playlist-desc {
  margin: 0;
  padding: 0 16px;
  font-size: 14px;
  color: var(--ink-soft);
  line-height: 1.65;
}

.playlist-items {
  margin: 0;
  padding: 0 16px;
  list-style: none;
  border-top: 1px solid var(--rule);
  padding-top: 10px;
}

.playlist-items li {
  display: flex;
  gap: 8px;
  margin: 0 0 6px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--ink);
}

.item-num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--indigo);
  padding-top: 1px;
}

.card-link {
  margin: 4px 16px 0;
  align-self: flex-start;
  font-size: 13px;
  font-family: var(--font-mono);
  color: var(--indigo);
  text-decoration: none;
  border-bottom: 1px solid var(--rule);
  padding-bottom: 2px;
}

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

.version-strip {
  padding: 32px 0;
  border-top: 1px solid var(--rule);
}

.version-strip h2 {
  margin: 0 0 8px;
}

.version-strip .section-lead {
  margin: 0 0 18px;
}

.version-rows {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--rule);
}

.version-row {
  display: grid;
  grid-template-columns: 90px minmax(0, 1fr) auto;
  gap: 16px;
  align-items: center;
  padding: 12px 0;
  border-bottom: 1px solid var(--rule);
  margin: 0;
}

.version-code {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--indigo);
  font-weight: 600;
  letter-spacing: 0.02em;
}

.version-scope {
  font-size: 14px;
  color: var(--ink);
  line-height: 1.6;
  min-width: 0;
}

.version-link {
  font-size: 13px;
  font-family: var(--font-mono);
  color: var(--ink-soft);
  text-decoration: none;
  white-space: nowrap;
}

.version-link:hover,
.version-link:focus-visible {
  color: var(--accent);
  text-decoration: underline;
}

.contribute-steps {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
  gap: 40px;
  padding: 32px 0;
  border-top: 1px solid var(--rule);
  align-items: start;
}

.steps-text {
  min-width: 0;
}

.steps-text h2 {
  margin: 0 0 12px;
}

.steps-text > p {
  margin: 0 0 18px;
  color: var(--ink-soft);
  font-size: 15px;
}

.steps-entry {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  min-width: 0;
}

.entry-card {
  display: grid;
  gap: 4px;
  padding: 16px;
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 3px;
  text-decoration: none;
  color: var(--ink);
  min-height: 44px;
}

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

.entry-card:hover .entry-title,
.entry-card:focus-visible .entry-title {
  color: var(--accent);
}

.entry-title {
  font-size: 15px;
  font-weight: 700;
}

.entry-desc {
  font-size: 13px;
  color: var(--ink-soft);
  line-height: 1.6;
}

.site-index {
  padding: 32px 0 8px;
  border-top: 1px solid var(--rule);
}

.site-index h2 {
  margin: 0 0 16px;
}

.site-index-rows {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--rule);
}

.site-index-row {
  display: grid;
  grid-template-columns: minmax(0, 180px) minmax(0, 1fr);
  gap: 20px;
  align-items: baseline;
  padding: 12px 0;
  border-bottom: 1px solid var(--rule);
  margin: 0;
}

.site-index-row a {
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
  text-decoration: none;
}

.site-index-row a:hover,
.site-index-row a:focus-visible {
  color: var(--accent);
  text-decoration: underline;
}

.site-index-row span {
  font-size: 14px;
  color: var(--ink-soft);
  line-height: 1.65;
}

/* ============================================================
   pages — overview
   ============================================================ */

.scope-compare {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
  margin: 18px 0 0;
}

.scope-column {
  min-width: 0;
  padding: 16px 18px;
  border: 1px solid var(--rule);
  border-radius: 3px;
  background: var(--surface);
}

.scope-column h3 {
  margin: 0 0 10px;
  font-size: 16px;
}

.scope-included h3 {
  color: var(--indigo);
}

.scope-excluded h3 {
  color: var(--accent);
}

.scope-list {
  margin: 0;
  padding-left: 1.1em;
}

.scope-list li {
  font-size: 14px;
  line-height: 1.7;
  margin-bottom: 8px;
}

.glossary-list {
  margin: 18px 0 0;
  border-top: 1px solid var(--rule);
}

.glossary-item {
  display: grid;
  grid-template-columns: minmax(0, 150px) minmax(0, 1fr);
  gap: 18px;
  padding: 12px 0;
  border-bottom: 1px solid var(--rule);
}

.glossary-item dt {
  font-weight: 600;
}

.glossary-item .term {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--indigo);
  background: var(--wash);
  padding: 2px 6px;
  border-radius: 2px;
}

.glossary-item dd {
  font-size: 14px;
  color: var(--ink);
  line-height: 1.7;
  min-width: 0;
}

.basis-list {
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
  counter-reset: basis;
}

.basis-list li {
  padding: 14px 0;
  border-top: 1px solid var(--rule);
  margin: 0;
}

.basis-list li:first-child {
  border-top: 0;
  padding-top: 0;
}

.basis-list li h3 {
  margin: 0 0 6px;
  font-size: 16px;
}

.basis-list li p {
  margin: 0;
  font-size: 14px;
  color: var(--ink-soft);
  line-height: 1.7;
}

.relation-list {
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--rule);
}

.relation-row {
  display: grid;
  grid-template-columns: minmax(0, 140px) minmax(0, 1fr) auto;
  gap: 16px;
  align-items: center;
  padding: 12px 0;
  border-bottom: 1px solid var(--rule);
  margin: 0;
}

.relation-name {
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
}

.relation-desc {
  font-size: 14px;
  color: var(--ink-soft);
  line-height: 1.65;
  min-width: 0;
}

.relation-link {
  font-size: 13px;
  font-family: var(--font-mono);
  color: var(--indigo);
  text-decoration: none;
  white-space: nowrap;
}

.relation-link:hover,
.relation-link:focus-visible {
  color: var(--accent);
  text-decoration: underline;
}

/* ============================================================
   pages — channels
   ============================================================ */

.section-conclusion .plain-list {
  margin: 12px 0 0;
}

.channel-tag-bar {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 6px;
  margin: 0 0 6px;
  -webkit-overflow-scrolling: touch;
}

.channel-tag {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  min-height: 36px;
  padding: 0 14px;
  font-size: 13px;
  font-family: var(--font-mono);
  color: var(--indigo);
  text-decoration: none;
  border: 1px solid var(--rule);
  border-radius: 3px;
  background: var(--surface);
  white-space: nowrap;
}

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

.channel-tag.is-active {
  background: var(--indigo);
  border-color: var(--indigo);
  color: #fff;
}

.channel-tag.is-active:hover,
.channel-tag.is-active:focus-visible {
  color: #fff;
}

.channel-row {
  display: grid;
  grid-template-columns: minmax(0, 220px) minmax(0, 1fr);
  gap: 24px;
  padding: 22px 0;
  border-top: 1px solid var(--rule);
  align-items: start;
}

.channel-row:first-of-type {
  border-top: 0;
  padding-top: 8px;
}

.channel-row-media {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.channel-num {
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
  color: var(--indigo);
}

.channel-figure {
  margin: 0;
  border: 1px solid var(--rule);
  border-radius: 3px;
  overflow: hidden;
  background: var(--surface);
}

.channel-figure img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  background: var(--wash);
}

.channel-figure figcaption {
  margin: 0;
  padding: 8px 10px;
  border-top: 1px solid var(--rule);
  font-size: 12px;
  color: var(--ink-soft);
}

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

.channel-row-body h3 {
  margin: 0 0 8px;
  font-size: 19px;
}

.channel-row-body > p {
  margin: 0 0 12px;
  font-size: 15px;
  color: var(--ink);
  line-height: 1.7;
}

.channel-facts {
  display: grid;
  grid-template-columns: minmax(0, 90px) minmax(0, 1fr);
  gap: 6px 14px;
  margin: 0;
  padding-top: 12px;
  border-top: 1px dashed var(--rule);
}

.channel-facts dt {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--ink-soft);
  letter-spacing: 0.02em;
}

.channel-facts dd {
  font-size: 14px;
  color: var(--ink);
  line-height: 1.65;
  min-width: 0;
}

.section-choose .plain-list,
.section-relate .plain-list {
  margin: 12px 0 0;
}

.relate-table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0 0;
  font-size: 14px;
}

.relate-table th,
.relate-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--rule);
  text-align: left;
  vertical-align: top;
}

.relate-table th {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--ink-soft);
  letter-spacing: 0.02em;
  font-weight: 600;
}

/* ============================================================
   pages — playlists
   ============================================================ */

.playlist-block {
  display: grid;
  grid-template-columns: minmax(0, 240px) minmax(0, 1fr);
  gap: 24px;
  padding: 24px 0;
  border-top: 1px solid var(--rule);
  align-items: start;
}

.playlist-block:first-of-type {
  border-top: 0;
  padding-top: 8px;
}

.playlist-media {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.playlist-number {
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
  color: var(--indigo);
}

.playlist-media .media-figure {
  margin: 0;
}

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

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

.playlist-body h3 {
  margin: 0 0 8px;
  font-size: 19px;
}

.playlist-logic {
  margin: 0 0 10px;
  font-size: 15px;
  line-height: 1.7;
}

.playlist-tag {
  margin: 0 0 12px;
  font-size: 13px;
  font-family: var(--font-mono);
}

.playlist-tag a {
  color: var(--indigo);
  text-decoration: none;
  border-bottom: 1px solid var(--rule);
  padding-bottom: 1px;
}

.playlist-tag a:hover,
.playlist-tag a:focus-visible {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.entry-list {
  margin: 0 0 12px;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--rule);
}

.entry-item {
  display: flex;
  gap: 10px;
  padding: 8px 0;
  border-bottom: 1px solid var(--rule);
  margin: 0;
  font-size: 14px;
  line-height: 1.65;
}

.entry-index {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--indigo);
  padding-top: 2px;
}

.playlist-fit {
  margin: 0;
  font-size: 14px;
  color: var(--ink-soft);
  line-height: 1.7;
}

#usage .step-list {
  margin-top: 8px;
}

#usage .step-item {
  align-items: flex-start;
}

#maintenance .notice {
  margin-top: 14px;
}

.link-list {
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
}

.link-list li {
  margin: 0;
}

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

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

.related-links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 18px;
  margin: 24px 0 0;
  padding: 16px 0 0;
  border-top: 1px solid var(--rule);
  font-size: 14px;
}

.related-links-label {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--ink-soft);
  letter-spacing: 0.02em;
}

.related-links-item {
  color: var(--indigo);
  text-decoration: none;
  border-bottom: 1px solid var(--rule);
  padding-bottom: 1px;
}

.related-links-item:hover,
.related-links-item:focus-visible {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* ============================================================
   pages — fieldnotes
   ============================================================ */

.quick-answer {
  padding: 20px 0 24px;
  border-top: 1px solid var(--rule);
}

.quick-answer h2 {
  margin: 0 0 8px;
}

.quick-answer-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
}

.quick-answer-item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  gap: 12px;
  align-items: baseline;
  padding: 12px 14px;
  background: var(--wash);
  border-left: 3px solid var(--indigo);
  border-radius: 2px;
  margin: 0;
}

.quick-answer-tag {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--indigo);
  font-weight: 600;
  letter-spacing: 0.02em;
}

.quick-answer-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.65;
  min-width: 0;
}

.quick-answer-device {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--ink-soft);
  white-space: nowrap;
}

.qa-section {
  padding: 28px 0;
  border-top: 1px solid var(--rule);
}

.qa-section h2 {
  margin: 0 0 8px;
}

.qa-item {
  border-top: 1px solid var(--rule);
  margin: 0;
}

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

.qa-summary {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 48px;
  padding: 12px 0;
  font-size: 16px;
  font-weight: 600;
  color: var(--ink);
  cursor: pointer;
  list-style: none;
}

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

.qa-summary::before {
  content: "+";
  flex: 0 0 auto;
  width: 20px;
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--indigo);
  line-height: 1;
}

.qa-item[open] .qa-summary::before {
  content: "−";
}

.qa-summary:hover,
.qa-summary:focus-visible {
  color: var(--accent);
}

.qa-body {
  padding: 0 0 16px 30px;
}

.qa-body p {
  margin: 0 0 10px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink);
}

.qa-device {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--ink-soft);
}

.selfcheck-section {
  padding: 28px 0;
  border-top: 1px solid var(--rule);
}

.selfcheck-section h2 {
  margin: 0 0 8px;
}

.selfcheck-section .step-list {
  margin-top: 18px;
}

.feedback-section {
  padding: 28px 0;
  border-top: 1px solid var(--rule);
}

.feedback-section h2 {
  margin: 0 0 8px;
}

.feedback-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
  margin-top: 16px;
}

.feedback-col {
  min-width: 0;
  padding: 16px 18px;
  border: 1px solid var(--rule);
  border-radius: 3px;
  background: var(--surface);
}

.feedback-subtitle {
  margin: 0 0 10px;
  font-size: 16px;
  color: var(--indigo);
}

.feedback-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.feedback-item {
  display: flex;
  gap: 8px;
  padding: 6px 0;
  margin: 0;
  font-size: 14px;
  line-height: 1.65;
}

.feedback-num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--indigo);
  padding-top: 2px;
}

.feedback-col-entry p {
  margin: 0 0 12px;
  font-size: 14px;
  color: var(--ink-soft);
  line-height: 1.7;
}

.entry-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  margin: 0 10px 10px 0;
  font-size: 14px;
  font-weight: 600;
  color: #fff;
  background: var(--accent);
  border: 1px solid var(--accent);
  border-radius: 3px;
  text-decoration: none;
}

.entry-link:hover,
.entry-link:focus-visible {
  background: #993a19;
  color: #fff;
  text-decoration: none;
}

.entry-link-secondary {
  background: var(--surface);
  color: var(--ink);
  border-color: var(--rule);
}

.entry-link-secondary:hover,
.entry-link-secondary:focus-visible {
  background: var(--surface);
  color: var(--accent);
  border-color: var(--accent);
}

/* ============================================================
   pages — versions
   ============================================================ */

.version-list {
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--rule);
}

.version-list .version-row {
  display: grid;
  grid-template-columns: minmax(0, 90px) minmax(0, 1fr);
  gap: 20px;
  align-items: start;
  padding: 16px 0;
  border-bottom: 1px solid var(--rule);
}

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

.version-body h3 {
  margin: 0 0 6px;
  font-size: 16px;
}

.version-body p {
  margin: 0 0 6px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--ink-soft);
}

.version-body .version-scope {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--ink-soft);
}

.version-fix {
  font-size: 13px;
  color: var(--indigo);
  font-family: var(--font-mono);
}

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

#rules .plain-list,
#follow .plain-list,
#current .plain-list {
  margin: 12px 0 0;
}

/* ============================================================
   pages — contribute
   ============================================================ */

.type-list {
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--rule);
}

.type-item {
  display: grid;
  grid-template-columns: minmax(0, 40px) minmax(0, 1fr);
  gap: 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--rule);
  margin: 0;
}

.type-index {
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
  color: var(--indigo);
  padding-top: 2px;
}

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

.type-body h3 {
  margin: 0 0 4px;
  font-size: 16px;
}

.type-body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--ink-soft);
}

.materials-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 24px;
  margin-top: 16px;
  align-items: start;
}

.materials-list-col {
  min-width: 0;
}

.materials-list-col .step-list {
  margin: 0;
}

.materials-figure {
  margin: 0;
}

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

.process-list {
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--rule);
}

.process-item {
  display: grid;
  grid-template-columns: minmax(0, 44px) minmax(0, 1fr);
  gap: 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--rule);
  margin: 0;
}

.process-index {
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
  color: var(--indigo);
  padding-top: 2px;
}

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

.process-body h3 {
  margin: 0 0 4px;
  font-size: 16px;
}

.process-body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--ink-soft);
}

#process .notice {
  margin-top: 18px;
}

#record .section-links {
  margin-top: 14px;
}

/* ============================================================
   pages — 404
   ============================================================ */

.error-main {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 48px var(--pad) 64px;
}

.error-inner {
  max-width: var(--read);
}

.error-hero {
  padding-bottom: 32px;
  border-bottom: 1px solid var(--rule);
}

.error-code {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--indigo);
}

.error-hero h1 {
  margin: 0 0 14px;
}

.error-lead {
  margin: 0 0 22px;
  font-size: 16px;
  color: var(--ink-soft);
  line-height: 1.7;
}

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

.error-btn-primary,
.error-btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 20px;
  border-radius: 3px;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
}

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

.error-btn-primary:hover,
.error-btn-primary:focus-visible {
  background: #993a19;
  color: #fff;
  text-decoration: none;
}

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

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

.error-paths {
  padding-top: 32px;
}

.error-paths h2 {
  margin: 0 0 8px;
}

.error-paths-intro {
  margin: 0 0 18px;
  font-size: 15px;
  color: var(--ink-soft);
}

.error-path-list {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--rule);
}

.error-path-item {
  display: grid;
  grid-template-columns: minmax(0, 180px) minmax(0, 1fr);
  gap: 20px;
  align-items: baseline;
  padding: 12px 0;
  border-bottom: 1px solid var(--rule);
  margin: 0;
}

.error-path-link {
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
  text-decoration: none;
}

.error-path-link:hover,
.error-path-link:focus-visible {
  color: var(--accent);
  text-decoration: underline;
}

.error-path-desc {
  font-size: 14px;
  color: var(--ink-soft);
  line-height: 1.65;
}

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

@media (max-width: 1024px) {
  .page-layout {
    grid-template-columns: 210px minmax(0, 1fr);
    gap: 36px;
  }

  .toc-panel,
  .toc-rail,
  .page-toc,
  .aside-toc {
    display: none;
  }

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

  .site-nav {
    gap: 18px;
  }

  .nav-group-label {
    display: none;
  }

  .hero-split,
  .conclusion,
  .contribute-steps {
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
  }

  .hero-index {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    grid-template-rows: none;
  }

  .playlist-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
  }
}

@media (max-width: 900px) {
  .site-nav {
    display: none;
  }

  .menu-toggle {
    display: inline-flex;
    margin-left: auto;
  }

  .header-inner {
    gap: 16px;
    padding: 12px var(--pad);
  }

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

  .scope-compare,
  .feedback-grid,
  .materials-split {
    grid-template-columns: minmax(0, 1fr);
  }
}

@media (max-width: 720px) {
  :root {
    --pad: 16px;
  }

  .page-layout {
    display: flex;
    flex-direction: column;
    gap: 0;
    padding-bottom: 40px;
  }

  .page-layout > .inner-main,
  .page-layout > .site-main {
    order: 1;
    width: 100%;
    min-width: 0;
    max-width: none;
  }

  .page-layout > .version-panel,
  .page-layout > .aside-version,
  .page-layout > .version-rail {
    order: 2;
    position: static;
    width: 100%;
    margin-top: 24px;
    padding-top: 18px;
    border-top: 1px solid var(--rule);
  }

  .page-layout > .toc-panel,
  .page-layout > .toc-rail,
  .page-layout > .page-toc,
  .page-layout > .aside-toc {
    order: 3;
    display: none;
  }

  .breadcrumb {
    padding: 14px var(--pad) 0;
  }

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

  .content-section > h2,
  .doc-section > h2,
  .section > h2 {
    font-size: 21px;
  }

  .status-strip {
    grid-template-columns: minmax(0, 1fr);
    margin: 0 calc(var(--pad) * -1);
    padding: 0 var(--pad);
  }

  .status-cell {
    border-left: 0;
    border-top: 1px solid var(--rule);
    padding: 10px 0;
  }

  .status-cell:first-child {
    border-top: 0;
  }

  .hero-split {
    padding: 24px 0 26px;
  }

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

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

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

  .btn-primary,
  .btn-secondary {
    width: 100%;
  }

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

  .conclusion,
  .contribute-steps {
    padding: 26px 0;
  }

  .dir-row {
    grid-template-columns: 44px minmax(0, 1fr);
    grid-template-areas:
      "num name"
      "desc desc"
      "link link";
    gap: 4px 12px;
    align-items: start;
    padding: 14px 0;
  }

  .dir-num {
    grid-area: num;
  }

  .dir-name {
    grid-area: name;
  }

  .dir-desc {
    grid-area: desc;
    margin-top: 2px;
  }

  .dir-link {
    grid-area: link;
    justify-self: start;
    margin-top: 8px;
  }

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

  .version-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px;
    align-items: start;
  }

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

  .site-index-row,
  .error-path-item {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px;
  }

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

  .channel-row,
  .playlist-block {
    grid-template-columns: minmax(0, 1fr);
    gap: 16px;
    padding: 20px 0;
  }

  .channel-row-media,
  .playlist-media {
    flex-direction: row;
    align-items: flex-start;
    gap: 12px;
  }

  .channel-row-media .channel-num,
  .playlist-media .playlist-number {
    padding-top: 4px;
  }

  .channel-figure,
  .playlist-media .media-figure {
    flex: 1 1 auto;
    min-width: 0;
  }

  .channel-facts {
    grid-template-columns: minmax(0, 84px) minmax(0, 1fr);
  }

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

  .relation-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px;
    align-items: start;
  }

  .relation-link {
    justify-self: start;
    margin-top: 2px;
  }

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

  .quick-answer-device {
    justify-self: start;
  }

  .qa-body {
    padding-left: 0;
  }

  .type-item,
  .process-item {
    grid-template-columns: minmax(0, 34px) minmax(0, 1fr);
    gap: 12px;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
    padding: 20px var(--pad);
  }

  .footer-links {
    flex-direction: column;
    gap: 0;
    width: 100%;
  }

  .footer-links a {
    display: flex;
    align-items: center;
    min-height: 44px;
    border-bottom: 1px solid var(--rule);
    width: 100%;
  }

  .footer-copy {
    font-size: 12px;
  }

  .error-main {
    padding: 32px var(--pad) 48px;
  }

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

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

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.001ms !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}

/* 程序验收反馈：移动端正文优先 */
@media (max-width: 768px) {
  .site-main :is(.page-content, .main-content, .content-main) {
    order: 1;
  }

  .site-main :is(aside, .sidebar) {
    order: 2;
  }
}