:root {
  --ink: #1f2a44;
  --ink-soft: #38445e;
  --muted: #6b7280;
  --accent: #c77d2e;
  --accent-deep: #a8641f;
  --paper: #f7f5f1;
  --paper-raised: #ffffff;
  --line: #d9d5cd;
  --line-strong: #c3bdb2;
  --radius: 6px;
  --radius-sm: 4px;
  --shadow: 0 1px 2px rgba(31, 42, 68, 0.06), 0 8px 24px rgba(31, 42, 68, 0.05);
  --maxw: 1180px;
  --sidebar-w: 244px;
  --gap: 28px;
}

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

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

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

body {
  margin: 0;
  background-color: var(--paper);
  color: var(--ink);
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans CJK SC", system-ui, -apple-system, "Segoe UI", sans-serif;
  font-size: 16px;
  line-height: 1.75;
  font-weight: 400;
  letter-spacing: 0;
}

h1, h2, h3, h4 {
  margin: 0;
  color: var(--ink);
  font-weight: 700;
  line-height: 1.3;
}

p {
  margin: 0;
}

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

a {
  color: var(--ink);
  text-decoration: none;
  transition: color 0.18s ease, background-color 0.18s ease, border-color 0.18s ease;
}

a:hover {
  color: var(--accent-deep);
}

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

figure {
  margin: 0;
}

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

button {
  font: inherit;
  color: inherit;
}

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

.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 — shell
   ========================================================================== */

.site-body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  background-color: var(--paper);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background-color: var(--ink);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.site-header .brand {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 20px;
  color: #f4f1ea;
}

.site-header .brand:hover {
  color: #ffffff;
}

.brand-mark {
  width: 30px;
  height: 30px;
  border-radius: var(--radius-sm);
  object-fit: contain;
  background-color: rgba(255, 255, 255, 0.08);
}

.brand-name {
  font-size: 1.0625rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  white-space: nowrap;
}

.site-nav {
  background-color: var(--ink);
}

.nav-list {
  display: flex;
  flex-wrap: wrap;
  align-items: stretch;
  gap: 2px;
  padding: 0 12px 10px;
}

.nav-item {
  display: flex;
}

.nav-item a {
  display: flex;
  align-items: center;
  min-height: 44px;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  color: #cfd4e0;
  font-size: 0.9375rem;
  white-space: nowrap;
}

.nav-item a:hover {
  background-color: rgba(255, 255, 255, 0.09);
  color: #ffffff;
}

.nav-item.is-current a {
  background-color: var(--accent);
  color: #ffffff;
  font-weight: 600;
}

.nav-toggle {
  display: none;
  position: absolute;
  top: 12px;
  right: 16px;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid rgba(255, 255, 255, 0.24);
  border-radius: var(--radius-sm);
  background-color: transparent;
  cursor: pointer;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
}

.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  background-color: #f4f1ea;
}

.site-main {
  flex: 1 1 auto;
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 32px 24px 64px;
}

.inner-main {
  padding-top: 24px;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 18px;
  font-size: 0.875rem;
  color: var(--muted);
}

.breadcrumb a {
  color: var(--muted);
  text-decoration: underline;
  text-underline-offset: 3px;
}

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

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

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

.page-header {
  padding-bottom: 22px;
  margin-bottom: 30px;
  border-bottom: 2px solid var(--ink);
}

.page-description {
  margin-bottom: 8px;
  color: var(--accent-deep);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.page-title {
  font-size: 2rem;
  line-height: 1.28;
}

.page-intro,
.page-lead {
  margin-top: 14px;
  max-width: 74ch;
  color: var(--ink-soft);
  font-size: 1rem;
}

.site-footer {
  margin-top: auto;
  padding: 40px 24px 28px;
  background-color: var(--ink);
  color: #c3c9d6;
}

.footer-intro {
  max-width: var(--maxw);
  margin: 0 auto 28px;
  padding-bottom: 22px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
  color: #aab2c3;
  font-size: 0.9375rem;
}

.footer-groups {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 26px;
  max-width: var(--maxw);
  margin: 0 auto;
}

.footer-group-title {
  margin-bottom: 12px;
  color: #f4f1ea;
  font-size: 0.9375rem;
  font-weight: 700;
}

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

.footer-list a {
  display: inline-block;
  min-height: 24px;
  color: #aab2c3;
  font-size: 0.875rem;
}

.footer-list a:hover {
  color: #ffffff;
}

.footer-copyright {
  max-width: var(--maxw);
  margin: 32px auto 0;
  padding-top: 18px;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  color: #8b93a5;
  font-size: 0.8125rem;
}

/* ==========================================================================
   components — shared
   ========================================================================== */

.section {
  margin-bottom: 52px;
}

.section-title {
  font-size: 1.375rem;
}

.section-head {
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line);
}

.section-index {
  margin-bottom: 6px;
  color: var(--accent-deep);
  font-family: "SFMono-Regular", "Menlo", "Consolas", monospace;
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.1em;
}

.section-lead,
.section-note,
.section-intro {
  margin-top: 10px;
  max-width: 76ch;
  color: var(--ink-soft);
  font-size: 0.9688rem;
}

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

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 32px;
  color: var(--accent-deep);
  font-size: 0.9375rem;
  font-weight: 600;
  border-bottom: 1px solid transparent;
}

.link-arrow::after {
  content: "→";
  font-size: 0.875rem;
}

.link-arrow:hover {
  color: var(--ink);
  border-bottom-color: var(--ink);
}

.subsection-title {
  margin-bottom: 12px;
  font-size: 1.0625rem;
}

.step-list,
.guide-step-list,
.guide-return-list {
  counter-reset: none;
}

.step-item,
.guide-step,
.guide-return-item {
  position: relative;
  padding: 16px 0 16px 0;
  border-top: 1px solid var(--line);
}

.step-item:last-child,
.guide-step:last-child,
.guide-return-item:last-child {
  border-bottom: 1px solid var(--line);
}

.step-no,
.step-index {
  display: inline-block;
  margin-bottom: 6px;
  color: var(--accent-deep);
  font-family: "SFMono-Regular", "Menlo", "Consolas", monospace;
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.step-title {
  font-size: 1.0625rem;
}

.step-desc,
.step-text {
  margin-top: 8px;
  max-width: 72ch;
  color: var(--ink-soft);
  font-size: 0.9688rem;
}

.step-desc a,
.step-text a {
  color: var(--accent-deep);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.step-desc a:hover,
.step-text a:hover {
  color: var(--ink);
}

.scope-list,
.types-list,
.rule-list {
  margin-top: 10px;
}

.scope-list li,
.types-list li,
.rule-list li {
  position: relative;
  padding-left: 18px;
  color: var(--ink-soft);
  font-size: 0.9375rem;
}

.scope-list li + li,
.types-list li + li,
.rule-list li + li {
  margin-top: 8px;
}

.scope-list li::before,
.types-list li::before,
.rule-list li::before {
  content: "";
  position: absolute;
  top: 0.72em;
  left: 2px;
  width: 6px;
  height: 6px;
  background-color: var(--accent);
  border-radius: 50%;
}

/* figures */

.hero-media,
.collection-media,
.division-figure,
.figure,
.media-figure,
.guide-figure {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background-color: var(--paper-raised);
}

.hero-media img,
.collection-media img,
.division-figure img,
.figure img,
.media-figure img,
.guide-figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-media figcaption,
.division-figure figcaption,
.figure figcaption,
.media-figure figcaption,
.guide-figure figcaption {
  padding: 10px 14px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.8438rem;
  line-height: 1.6;
}

/* buttons */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 10px 22px;
  border: 1px solid var(--ink);
  border-radius: var(--radius-sm);
  font-size: 0.9688rem;
  font-weight: 600;
}

.btn-primary {
  background-color: var(--ink);
  color: #ffffff;
}

.btn-primary:hover {
  background-color: var(--accent-deep);
  border-color: var(--accent-deep);
  color: #ffffff;
}

.btn-ghost {
  background-color: transparent;
  color: var(--ink);
}

.btn-ghost:hover {
  background-color: var(--ink);
  color: #ffffff;
}

/* tables */

.fields-table,
.field-table,
.mapping-table {
  font-size: 0.9375rem;
}

.fields-table caption,
.field-table caption,
.mapping-table caption {
  text-align: left;
}

.fields-table th,
.fields-table td,
.field-table th,
.field-table td,
.mapping-table th,
.mapping-table td {
  padding: 12px 14px;
  border: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.fields-table thead th,
.field-table thead th,
.mapping-table thead th {
  background-color: #efece6;
  color: var(--ink);
  font-weight: 700;
  white-space: nowrap;
}

.fields-table tbody th,
.field-table tbody th,
.mapping-table tbody th {
  background-color: #f2efe9;
  font-weight: 600;
}

.field-name {
  color: var(--ink);
  white-space: nowrap;
}

/* FAQ */

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

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

.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 52px;
  padding: 14px 4px;
  color: var(--ink);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
}

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

.faq-question::after {
  content: "+";
  flex: 0 0 auto;
  color: var(--accent-deep);
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1;
}

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

.faq-question:hover {
  color: var(--accent-deep);
}

.faq-answer {
  padding: 0 4px 18px;
  max-width: 76ch;
  color: var(--ink-soft);
  font-size: 0.9375rem;
}

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

.home-main {
  padding-top: 28px;
}

/* hero */

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
  grid-template-areas:
    "copy media"
    "entries entries";
  gap: 28px 34px;
  padding-bottom: 40px;
  margin-bottom: 48px;
  border-bottom: 1px solid var(--line);
}

.hero-copy {
  grid-area: copy;
  align-self: center;
}

.hero-kicker {
  margin-bottom: 10px;
  color: var(--accent-deep);
  font-family: "SFMono-Regular", "Menlo", "Consolas", monospace;
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.1em;
}

.hero-title {
  font-size: 2.25rem;
  line-height: 1.24;
}

.hero-text {
  margin-top: 16px;
  max-width: 46ch;
  color: var(--ink-soft);
  font-size: 1.0313rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.hero-media {
  grid-area: media;
  align-self: stretch;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow);
}

.hero-media img {
  flex: 1 1 auto;
  min-height: 240px;
  aspect-ratio: 16 / 10;
}

.hero-entries {
  grid-area: entries;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.entry-card {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 20px 22px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background-color: var(--paper-raised);
}

.entry-card:hover {
  border-color: var(--accent);
  background-color: #fffdf9;
}

.entry-index {
  color: var(--accent-deep);
  font-family: "SFMono-Regular", "Menlo", "Consolas", monospace;
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.1em;
}

.entry-name {
  font-size: 1.125rem;
  font-weight: 700;
}

.entry-desc {
  color: var(--muted);
  font-size: 0.9063rem;
}

/* channels overview */

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

.channel-row {
  display: grid;
  grid-template-columns: 56px minmax(160px, 0.9fr) minmax(200px, 1.1fr) minmax(200px, 1.2fr) minmax(140px, 0.8fr);
  gap: 18px;
  align-items: baseline;
  padding: 18px 4px;
  border-bottom: 1px solid var(--line);
}

.channel-row:hover {
  background-color: #f1eee8;
}

.channel-no {
  color: var(--accent-deep);
  font-family: "SFMono-Regular", "Menlo", "Consolas", monospace;
  font-size: 0.9375rem;
  font-weight: 700;
}

.channel-name {
  font-size: 1.0625rem;
  font-weight: 700;
}

.channel-tendency,
.channel-scope,
.channel-type {
  color: var(--ink-soft);
  font-size: 0.9375rem;
}

.channel-type {
  color: var(--muted);
}

/* collections overview */

.collection-strips {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 22px;
}

.collection-strip {
  display: flex;
  flex-direction: column;
  padding: 18px 20px 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background-color: var(--paper-raised);
}

.collection-strip:hover {
  border-color: var(--accent);
}

.collection-media {
  margin-bottom: 16px;
  aspect-ratio: 4 / 3;
}

.collection-name {
  margin-bottom: 8px;
  font-size: 1.125rem;
}

.collection-theme {
  color: var(--ink-soft);
  font-size: 0.9375rem;
}

.collection-logic {
  margin-top: 10px;
  color: var(--ink-soft);
  font-size: 0.9375rem;
}

.collection-source {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px dashed var(--line-strong);
  color: var(--muted);
  font-size: 0.875rem;
}

/* fields summary */

.fields-summary {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
  gap: 30px;
  align-items: start;
}

.fields-table-wrap {
  min-width: 0;
  overflow-x: auto;
}

.boundary-note {
  padding: 20px 22px;
  border-left: 3px solid var(--accent);
  background-color: #f1eee8;
  border-radius: 0 var(--radius) var(--radius) 0;
}

.boundary-note p {
  color: var(--ink-soft);
  font-size: 0.9375rem;
}

.boundary-note p + p {
  margin-top: 12px;
}

.boundary-note .section-more {
  margin-top: 16px;
}

/* guide steps overview */

.section-guide .guide-steps {
  border-top: 1px solid var(--line-strong);
}

.section-guide .guide-step {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: 16px;
  align-items: baseline;
}

.section-guide .guide-step .step-link {
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--ink);
}

.section-guide .guide-step .step-link:hover {
  color: var(--accent-deep);
}

.section-guide .guide-step .step-desc {
  grid-column: 2;
  margin-top: 6px;
}

/* sitemap index */

.index-columns {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 22px;
}

.index-col {
  padding: 20px 20px 22px;
  border: 1px solid var(--line);
  border-top: 3px solid var(--ink);
  border-radius: var(--radius);
  background-color: var(--paper-raised);
}

.index-col-title {
  margin-bottom: 8px;
  font-size: 1.0625rem;
}

.index-col-desc {
  margin-bottom: 14px;
  color: var(--ink-soft);
  font-size: 0.9063rem;
}

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

.section-division .division-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.section-division .division-body p {
  max-width: 78ch;
  color: var(--ink-soft);
  font-size: 0.9688rem;
}

.division-figure {
  margin-top: 22px;
  aspect-ratio: 16 / 7;
}

.division-figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.section-channel-index .channel-rows {
  border-top: 1px solid var(--line-strong);
}

.section-channel-index .channel-row {
  grid-template-columns: 56px minmax(0, 1fr) minmax(180px, 0.7fr);
  align-items: start;
}

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

.channel-row-main .channel-name {
  margin-bottom: 6px;
}

.channel-orientation,
.channel-scope {
  color: var(--ink-soft);
  font-size: 0.9375rem;
}

.channel-scope {
  margin-top: 6px;
  color: var(--muted);
}

.channel-types {
  color: var(--ink-soft);
  font-size: 0.9063rem;
}

.channel-types-label {
  display: block;
  margin-bottom: 4px;
  color: var(--accent-deep);
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.06em;
}

.section-scope-types .scope-types-columns {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 30px;
}

.scope-column,
.types-column {
  padding: 20px 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background-color: var(--paper-raised);
}

.scope-column .column-title,
.types-column .column-title {
  margin-bottom: 10px;
  font-size: 1.0625rem;
}

.scope-column p,
.types-column p {
  color: var(--ink-soft);
  font-size: 0.9375rem;
}

.section-channel-to-collection .step-list {
  border-top: 1px solid var(--line-strong);
}

.section-channel-to-collection .step-item {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: 16px;
  align-items: baseline;
}

.section-footnote {
  margin-top: 18px;
}

.section-footnote a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 32px;
  color: var(--accent-deep);
  font-size: 0.9375rem;
  font-weight: 600;
}

.section-footnote a::after {
  content: "→";
}

.section-footnote a:hover {
  color: var(--ink);
}

/* ==========================================================================
   pages — collections
   ========================================================================== */

.section-collection-organization .section-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.section-collection-organization .section-body p {
  max-width: 78ch;
  color: var(--ink-soft);
  font-size: 0.9688rem;
}

.figure-collection-structure {
  margin-top: 22px;
  aspect-ratio: 16 / 7;
}

.figure-collection-structure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

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

.collection-block:last-of-type {
  border-bottom: 1px solid var(--line-strong);
}

.collection-head {
  margin-bottom: 14px;
}

.collection-index {
  margin-bottom: 6px;
  color: var(--accent-deep);
  font-family: "SFMono-Regular", "Menlo", "Consolas", monospace;
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.1em;
}

.collection-head .collection-name {
  font-size: 1.1875rem;
}

.collection-topic {
  margin-top: 6px;
  color: var(--ink-soft);
  font-size: 0.9375rem;
}

.collection-body .collection-logic {
  max-width: 78ch;
  color: var(--ink-soft);
  font-size: 0.9688rem;
}

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

.meta-item {
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background-color: var(--paper-raised);
  color: var(--ink-soft);
  font-size: 0.9063rem;
}

.meta-label {
  display: block;
  margin-bottom: 4px;
  color: var(--accent-deep);
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.06em;
}

.table-wrap {
  width: 100%;
  overflow-x: auto;
}

.mapping-table th[scope="row"] {
  white-space: nowrap;
}

.mapping-note {
  margin-top: 16px;
}

.mapping-note a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 32px;
  color: var(--accent-deep);
  font-size: 0.9375rem;
  font-weight: 600;
}

.mapping-note a::after {
  content: "→";
}

.mapping-note a:hover {
  color: var(--ink);
}

.section-collection-steps .step-list {
  border-top: 1px solid var(--line-strong);
}

.section-collection-steps .step-item {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: 16px;
  align-items: baseline;
}

.section-collection-steps .step-item .step-title,
.section-collection-steps .step-item .step-desc {
  grid-column: 2;
}

.section-collection-steps .step-item .step-desc {
  margin-top: 6px;
}

.steps-foot {
  margin-top: 18px;
}

.steps-foot a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 32px;
  color: var(--accent-deep);
  font-size: 0.9375rem;
  font-weight: 600;
}

.steps-foot a::after {
  content: "→";
}

.steps-foot a:hover {
  color: var(--ink);
}

/* ==========================================================================
   pages — fields
   ========================================================================== */

.page-layout.fields-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.65fr) minmax(0, 1fr);
  gap: 34px;
  align-items: start;
}

.fields-article {
  min-width: 0;
}

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

.content-section .section-title {
  margin-bottom: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}

.media-figure {
  margin: 18px 0 22px;
  aspect-ratio: 16 / 8;
}

.media-figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.field-table {
  margin-top: 6px;
}

.rule-columns {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 26px;
  margin-top: 16px;
}

.rule-column {
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background-color: var(--paper-raised);
}

.fields-aside {
  min-width: 0;
}

.fields-aside .content-section {
  padding: 22px 22px 24px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background-color: var(--paper-raised);
}

.fields-aside .content-section + .content-section {
  margin-top: 24px;
}

.fields-aside .section-title {
  font-size: 1.125rem;
}

.scope-item {
  padding: 14px 0;
  border-top: 1px solid var(--line);
}

.scope-item:first-child {
  border-top: none;
  padding-top: 4px;
}

.scope-title {
  margin-bottom: 6px;
  font-size: 1rem;
}

.scope-item p {
  color: var(--ink-soft);
  font-size: 0.9063rem;
}

.fields-aside .step-item {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr);
  gap: 12px;
  align-items: baseline;
}

.fields-aside .step-item .step-title,
.fields-aside .step-item p {
  grid-column: 2;
}

.fields-aside .step-item p {
  margin-top: 6px;
  color: var(--ink-soft);
  font-size: 0.9063rem;
}

.fields-aside .section-more {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin-top: 16px;
}

.fields-aside .section-more a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 32px;
  color: var(--accent-deep);
  font-size: 0.9063rem;
  font-weight: 600;
}

.fields-aside .section-more a::after {
  content: "→";
}

.fields-aside .section-more a:hover {
  color: var(--ink);
}

/* ==========================================================================
   pages — guide
   ========================================================================== */

.guide-steps,
.guide-criteria,
.guide-faq,
.guide-return {
  margin-bottom: 52px;
}

.guide-steps .section-title,
.guide-criteria .section-title,
.guide-faq .section-title,
.guide-return .section-title {
  margin-bottom: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}

.guide-figure {
  margin: 18px 0 22px;
  aspect-ratio: 16 / 7;
}

.guide-figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.guide-step-list {
  border-top: 1px solid var(--line-strong);
}

.guide-step-list .guide-step {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: 16px;
  align-items: baseline;
  padding: 18px 4px;
}

.guide-step-list .guide-step .step-title {
  grid-column: 2;
}

.guide-step-list .guide-step .step-desc {
  grid-column: 2;
  margin-top: 6px;
}

.criteria-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 22px;
}

.criteria-item {
  padding: 20px 22px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  background-color: var(--paper-raised);
}

.criteria-title {
  margin-bottom: 8px;
  font-size: 1.0625rem;
}

.criteria-text {
  color: var(--ink-soft);
  font-size: 0.9375rem;
}

.guide-return-list {
  border-top: 1px solid var(--line-strong);
}

.guide-return-list .guide-return-item {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: 16px;
  align-items: baseline;
  padding: 18px 4px;
}

.guide-return-list .guide-return-item .return-title {
  grid-column: 2;
  font-size: 1.0625rem;
}

.guide-return-list .guide-return-item .return-desc {
  grid-column: 2;
  margin-top: 6px;
  max-width: 72ch;
  color: var(--ink-soft);
  font-size: 0.9375rem;
}

.return-desc a {
  color: var(--accent-deep);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.return-desc a:hover {
  color: var(--ink);
}

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

.error-main {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 56px;
  padding-bottom: 72px;
}

.error-block {
  width: 100%;
  max-width: 640px;
  padding: 36px 32px 40px;
  border: 1px solid var(--line);
  border-top: 3px solid var(--accent);
  border-radius: var(--radius);
  background-color: var(--paper-raised);
}

.error-code {
  margin-bottom: 8px;
  color: var(--accent-deep);
  font-family: "SFMono-Regular", "Menlo", "Consolas", monospace;
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.12em;
}

.error-block h1 {
  font-size: 1.75rem;
}

.error-text {
  margin-top: 14px;
  color: var(--ink-soft);
  font-size: 0.9688rem;
}

.error-links {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 24px;
}

.error-links a {
  display: flex;
  align-items: center;
  min-height: 46px;
  padding: 10px 16px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  color: var(--ink);
  font-size: 0.9375rem;
  font-weight: 600;
}

.error-links a:hover {
  border-color: var(--accent);
  background-color: #fffdf9;
  color: var(--accent-deep);
}

.error-action {
  margin-top: 24px;
}

.error-home {
  display: inline-flex;
  align-items: center;
  min-height: 46px;
  padding: 10px 22px;
  border-radius: var(--radius-sm);
  background-color: var(--ink);
  color: #ffffff;
  font-size: 0.9688rem;
  font-weight: 600;
}

.error-home:hover {
  background-color: var(--accent-deep);
  color: #ffffff;
}

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

@media (max-width: 1024px) {
  .site-main {
    padding-left: 20px;
    padding-right: 20px;
  }

  .hero {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 24px;
  }

  .hero-title {
    font-size: 2rem;
  }

  .channel-row {
    grid-template-columns: 48px minmax(140px, 0.9fr) minmax(0, 1fr) minmax(0, 1.1fr);
  }

  .channel-row .channel-type {
    grid-column: 2 / -1;
    color: var(--muted);
    font-size: 0.875rem;
  }

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

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

  .page-layout.fields-layout {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 26px;
  }
}

@media (max-width: 860px) {
  .nav-toggle {
    display: flex;
  }

  .site-header .brand {
    padding-right: 72px;
  }

  .site-nav {
    padding: 0 12px;
  }

  .nav-list {
    display: none;
    flex-direction: column;
    gap: 4px;
    padding: 8px 0 14px;
  }

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

  .nav-item a {
    width: 100%;
    padding: 10px 14px;
    min-height: 46px;
  }

  .hero {
    grid-template-columns: minmax(0, 1fr);
    grid-template-areas:
      "copy"
      "media"
      "entries";
    gap: 24px;
  }

  .hero-title {
    font-size: 1.8125rem;
  }

  .hero-media img {
    min-height: 0;
    aspect-ratio: 16 / 9;
  }

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

  .fields-summary {
    grid-template-columns: minmax(0, 1fr);
    gap: 22px;
  }

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

  .fields-aside .content-section + .content-section {
    margin-top: 20px;
  }

  .footer-groups {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px;
  }
}

@media (max-width: 680px) {
  body {
    font-size: 15.5px;
  }

  .site-main {
    padding: 22px 16px 52px;
  }

  .inner-main {
    padding-top: 18px;
  }

  .page-header {
    padding-bottom: 16px;
    margin-bottom: 24px;
  }

  .page-title {
    font-size: 1.5rem;
  }

  .section {
    margin-bottom: 40px;
  }

  .section-title {
    font-size: 1.25rem;
  }

  .hero {
    padding-bottom: 30px;
    margin-bottom: 36px;
  }

  .hero-kicker {
    font-size: 0.75rem;
  }

  .hero-title {
    font-size: 1.625rem;
  }

  .hero-text {
    font-size: 0.9688rem;
  }

  .hero-actions .btn {
    flex: 1 1 100%;
  }

  .channel-row,
  .section-channel-index .channel-row {
    grid-template-columns: 44px minmax(0, 1fr);
    gap: 8px 14px;
    padding: 16px 2px;
  }

  .channel-row .channel-name,
  .section-channel-index .channel-row .channel-row-main {
    grid-column: 2;
  }

  .channel-row .channel-tendency,
  .channel-row .channel-scope,
  .channel-row .channel-type,
  .section-channel-index .channel-row .channel-types {
    grid-column: 2;
  }

  .collection-strips,
  .index-columns,
  .criteria-grid,
  .scope-types-columns,
  .rule-columns,
  .collection-meta,
  .error-links {
    grid-template-columns: minmax(0, 1fr);
  }

  .section-guide .guide-step,
  .section-channel-to-collection .step-item,
  .section-collection-steps .step-item,
  .guide-step-list .guide-step,
  .guide-return-list .guide-return-item,
  .fields-aside .step-item {
    grid-template-columns: 44px minmax(0, 1fr);
    gap: 10px 12px;
  }

  .error-block {
    padding: 26px 20px 30px;
  }

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

  .site-footer {
    padding: 32px 16px 24px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }
}