:root {
  --header-bg: #1b2430;
  --page-bg: #f5f6f8;
  --card-bg: #ffffff;
  --text-main: #1f2933;
  --text-sub: #5c6b7a;
  --line: #dde2e8;
  --accent: #b4472f;
  --notice-bg: #eef2f6;
  --radius: 6px;
  --container: 1120px;
  --prose: 760px;
}

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

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

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

body {
  margin: 0;
  background: var(--page-bg);
  color: var(--text-main);
  font-family: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  font-size: 15px;
  line-height: 1.75;
  text-rendering: optimizeLegibility;
}

h1,
h2,
h3,
h4 {
  margin: 0;
  font-weight: 700;
  color: var(--text-main);
}

p {
  margin: 0;
}

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

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

a:hover,
a:focus-visible {
  color: #8f3623;
  text-decoration: underline;
}

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

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

time,
.channel-no,
.record-date,
.records-date,
.principle-index,
.step-index,
.records-rule-num {
  font-family: ui-monospace, Menlo, Consolas, "Courier New", monospace;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--card-bg);
  color: var(--accent);
  padding: 10px 16px;
  z-index: 100;
}

.skip-link:focus {
  left: 8px;
  top: 8px;
}

/* ============ layout ============ */

.site-notice {
  background: var(--notice-bg);
  border-bottom: 1px solid var(--line);
}

.site-notice p {
  max-width: var(--container);
  margin: 0 auto;
  padding: 8px 24px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--text-sub);
}

.header-inner,
.footer-inner,
.site-main > .container,
.inner-main > .container,
.home-main > .home-section,
.home-main > .home-hero,
.inner-main > .breadcrumb,
.inner-main > .page-header,
.inner-main > .section,
.inner-main > .records-intro,
.inner-main > .records-timeline-section,
.inner-main > .records-types,
.inner-main > .records-related,
.inner-main > figure {
  max-width: var(--container);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

.site-header {
  background: var(--header-bg);
  border-bottom: 1px solid #0f1720;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 62px;
}

.brand {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  color: #f2f5f8;
  text-decoration: none;
  flex-shrink: 0;
}

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

.brand-mark {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0;
}

.brand-sub {
  font-size: 12px;
  color: #93a2b3;
}

.site-nav {
  display: flex;
}

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

.nav-list li {
  display: flex;
}

.nav-list a {
  display: flex;
  align-items: center;
  padding: 0 12px;
  min-height: 62px;
  color: #c8d2dd;
  font-size: 14px;
  text-decoration: none;
  border-bottom: 2px solid transparent;
}

.nav-list a:hover,
.nav-list a:focus-visible {
  color: #ffffff;
  border-bottom-color: #56636f;
  text-decoration: none;
}

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

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 0 10px;
  background: transparent;
  border: 1px solid #3a4756;
  border-radius: var(--radius);
  cursor: pointer;
}

.nav-toggle-bar {
  display: block;
  height: 2px;
  background: #c8d2dd;
  border-radius: 1px;
}

.site-main {
  display: block;
  padding-bottom: 48px;
}

.inner-main {
  padding-bottom: 48px;
}

/* ============ breadcrumb & page header ============ */

.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  padding-top: 20px;
  padding-bottom: 4px;
  font-size: 13px;
  color: var(--text-sub);
}

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

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

.breadcrumb-sep {
  color: #9aa7b4;
}

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

.page-header {
  padding-top: 12px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--line);
}

.page-title {
  font-size: 28px;
  line-height: 1.35;
  font-weight: 700;
  color: var(--text-main);
}

.page-description {
  margin-top: 8px;
  max-width: var(--prose);
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-sub);
}

/* ============ common section ============ */

.section {
  padding-top: 32px;
}

.section-title {
  font-size: 20px;
  line-height: 1.4;
  font-weight: 700;
}

.section-text,
.section-lead,
.section-intro {
  margin-top: 10px;
  max-width: var(--prose);
  color: var(--text-sub);
  line-height: 1.75;
}

.section-text a,
.section-lead a,
.section-intro a {
  color: var(--accent);
}

.section-head {
  margin-bottom: 16px;
}

.section-desc {
  margin-top: 6px;
  max-width: var(--prose);
  font-size: 14px;
  color: var(--text-sub);
}

.home-section {
  padding-top: 40px;
}

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

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

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

/* ============ figures ============ */

.hero-media,
.section-media,
.section-figure,
.guide-figure,
.field-figure,
.records-figure {
  margin: 0;
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.hero-media img,
.section-media img,
.section-figure img,
.guide-figure img,
.field-figure img,
.records-figure img {
  width: 100%;
  height: auto;
  object-fit: cover;
  aspect-ratio: 16 / 9;
}

.hero-media figcaption,
.section-media figcaption,
.section-figure figcaption,
.guide-figure figcaption,
.field-figure figcaption,
.records-figure-caption {
  padding: 10px 14px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--text-sub);
  border-top: 1px solid var(--line);
}

/* ============ home hero ============ */

.home-hero {
  padding-top: 32px;
}

.hero-console {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
  gap: 28px;
  align-items: start;
}

.hero-eyebrow {
  font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 12px;
  color: var(--accent);
  text-transform: uppercase;
}

.hero-title {
  margin-top: 10px;
  font-size: 28px;
  line-height: 1.35;
  font-weight: 700;
}

.hero-text {
  margin-top: 14px;
  max-width: var(--prose);
  color: var(--text-sub);
  line-height: 1.75;
}

.hero-media {
  margin-top: 20px;
}

.hero-tasks {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.task-block {
  display: flex;
  flex-direction: column;
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
}

.task-block:hover {
  border-color: #b9c3ce;
}

.task-title {
  font-size: 16px;
  line-height: 1.5;
  font-weight: 700;
}

.task-text {
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--text-sub);
  flex-grow: 1;
}

.task-link {
  margin-top: 12px;
  font-size: 14px;
  font-weight: 600;
}

/* ============ channel list (home) ============ */

.channel-list {
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.channel-row {
  display: grid;
  grid-template-columns: 64px minmax(120px, 0.9fr) minmax(0, 1.6fr) minmax(0, 1fr);
  gap: 16px;
  align-items: baseline;
  padding: 14px 18px;
  border-bottom: 1px solid var(--line);
}

.channel-row:last-child {
  border-bottom: none;
}

.channel-no {
  font-size: 13px;
  color: var(--accent);
}

.channel-name {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-main);
}

.channel-dir,
.channel-direction {
  font-size: 14px;
  color: var(--text-sub);
  line-height: 1.7;
}

.channel-range,
.channel-scope {
  font-size: 13px;
  color: var(--text-sub);
  line-height: 1.7;
}

/* ============ topic cards (home) ============ */

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

.topic-card {
  display: flex;
  flex-direction: column;
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
}

.topic-card:hover {
  border-color: #b9c3ce;
}

.topic-name {
  font-size: 16px;
  line-height: 1.5;
  font-weight: 700;
}

.topic-channels {
  margin-top: 8px;
  font-size: 13px;
  color: var(--accent);
}

.topic-note {
  margin-top: 8px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--text-sub);
  flex-grow: 1;
}

.topic-link {
  margin-top: 14px;
  font-size: 14px;
  font-weight: 600;
}

.section-media {
  margin-top: 20px;
}

/* ============ fields columns (home) ============ */

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

.fields-col {
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
}

.col-title {
  font-size: 16px;
  line-height: 1.5;
  font-weight: 700;
}

.field-list {
  margin: 12px 0 0;
}

.field-list dt {
  font-size: 14px;
  font-weight: 700;
  color: var(--text-main);
}

.field-list dd {
  margin: 2px 0 10px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-sub);
}

.field-list dd:last-child {
  margin-bottom: 0;
}

.boundary-list {
  margin-top: 12px;
}

.boundary-list li {
  position: relative;
  padding-left: 16px;
  margin-bottom: 8px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-sub);
}

.boundary-list li:last-child {
  margin-bottom: 0;
}

.boundary-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 6px;
  background: var(--accent);
  border-radius: 1px;
}

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

/* ============ records (home) ============ */

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

.record-group {
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
}

.record-month {
  font-size: 15px;
  font-weight: 700;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}

.record-list {
  margin-top: 10px;
}

.record-item {
  display: grid;
  grid-template-columns: 88px minmax(0, 1fr);
  gap: 4px 10px;
  padding: 8px 0;
  border-bottom: 1px dashed var(--line);
}

.record-item:last-child {
  border-bottom: none;
}

.record-date {
  font-size: 12px;
  color: var(--text-sub);
}

.record-type {
  font-size: 13px;
  color: var(--accent);
}

.record-scope {
  grid-column: 1 / -1;
  font-size: 13px;
  color: var(--text-sub);
  line-height: 1.65;
}

/* ============ site index (home) ============ */

.site-index {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 12px;
}

.index-cell {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 64px;
  padding: 12px;
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  color: var(--text-main);
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
}

.index-cell:hover,
.index-cell:focus-visible {
  color: var(--accent);
  border-color: #b9c3ce;
  text-decoration: none;
}

.index-note {
  margin-top: 4px;
  font-size: 12px;
  font-weight: 400;
  color: var(--text-sub);
}

/* ============ inner: channels ============ */

.intro-points {
  margin-top: 14px;
}

.intro-point {
  position: relative;
  padding-left: 18px;
  margin-bottom: 8px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-sub);
}

.intro-point:last-child {
  margin-bottom: 0;
}

.intro-point::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 6px;
  background: var(--accent);
  border-radius: 1px;
}

.channel-rows {
  margin-top: 16px;
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.channel-rows .channel-row {
  grid-template-columns: 64px minmax(140px, 0.8fr) minmax(0, 1.4fr) minmax(0, 1.4fr);
  align-items: start;
}

.channel-rows .channel-name {
  font-size: 15px;
}

.map-table {
  width: 100%;
  margin-top: 16px;
  border-collapse: collapse;
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.map-caption {
  caption-side: top;
  text-align: left;
  padding: 0 0 10px;
  font-size: 13px;
  color: var(--text-sub);
}

.map-table th,
.map-table td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  font-size: 14px;
  line-height: 1.7;
  vertical-align: top;
}

.map-table th {
  background: var(--notice-bg);
  font-weight: 700;
  color: var(--text-main);
}

.map-table tbody tr:last-child td {
  border-bottom: none;
}

.map-table td {
  color: var(--text-sub);
}

/* ============ inner: topics ============ */

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

.principle-item {
  display: flex;
  gap: 12px;
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
}

.principle-index {
  font-size: 13px;
  color: var(--accent);
  flex-shrink: 0;
}

.principle-text {
  font-size: 14px;
  line-height: 1.75;
  color: var(--text-sub);
}

.topic-entry {
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
  margin-top: 14px;
}

.topic-entry .topic-name {
  font-size: 16px;
}

.topic-meta {
  margin: 10px 0 0;
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: 4px 14px;
}

.topic-meta dt {
  font-size: 13px;
  font-weight: 700;
  color: var(--text-main);
}

.topic-meta dd {
  margin: 0 0 6px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--text-sub);
}

.cross-list {
  margin-top: 16px;
}

.cross-item {
  display: grid;
  grid-template-columns: 140px minmax(0, 1fr);
  gap: 14px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.cross-item:last-child {
  border-bottom: none;
}

.cross-label {
  font-size: 14px;
  font-weight: 700;
  color: var(--text-main);
}

.cross-text {
  font-size: 14px;
  line-height: 1.75;
  color: var(--text-sub);
}

/* ============ inner: guide ============ */

.guide-structure,
.guide-steps,
.guide-scenarios,
.guide-faq,
.guide-next {
  padding-top: 32px;
}

.guide-figure {
  margin-top: 16px;
}

.page-role-list {
  margin-top: 16px;
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-role-item {
  display: grid;
  grid-template-columns: 160px minmax(0, 1fr);
  gap: 14px;
  padding: 12px 18px;
  border-bottom: 1px solid var(--line);
}

.page-role-item:last-child {
  border-bottom: none;
}

.page-role-name {
  font-size: 14px;
  font-weight: 700;
  color: var(--text-main);
}

.page-role-desc {
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-sub);
}

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

.step-item {
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
}

.step-index {
  display: inline-block;
  font-size: 12px;
  color: var(--accent);
  margin-bottom: 6px;
}

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

.step-text {
  margin-top: 8px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--text-sub);
}

.step-link {
  margin-top: 10px;
  font-size: 14px;
}

.scenario-table-wrap {
  margin-top: 16px;
  overflow-x: auto;
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.scenario-table {
  width: 100%;
  min-width: 520px;
  border-collapse: collapse;
}

.scenario-caption {
  caption-side: top;
  text-align: left;
  padding: 12px 14px 0;
  font-size: 13px;
  color: var(--text-sub);
}

.scenario-table th,
.scenario-table td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  font-size: 14px;
  line-height: 1.7;
  vertical-align: top;
}

.scenario-table th {
  background: var(--notice-bg);
  font-weight: 700;
  color: var(--text-main);
}

.scenario-table tbody tr:last-child td {
  border-bottom: none;
}

.scenario-table td {
  color: var(--text-sub);
}

.faq-list {
  margin-top: 16px;
}

.faq-item {
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  margin-bottom: 10px;
}

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

.faq-question {
  padding: 14px 18px;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  list-style: none;
}

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

.faq-question::after {
  content: "+";
  float: right;
  font-weight: 400;
  color: var(--accent);
}

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

.faq-answer {
  padding: 0 18px 14px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--text-sub);
}

.next-list {
  margin-top: 16px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.next-item {
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.next-link {
  display: block;
  padding: 14px 16px;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-main);
  text-decoration: none;
}

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

/* ============ inner: fields ============ */

.field-figure {
  margin-top: 24px;
}

.field-defs,
.field-boundary,
.field-relations {
  padding-top: 32px;
}

.def-list {
  margin: 16px 0 0;
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.def-item {
  display: grid;
  grid-template-columns: 160px minmax(0, 1fr);
  gap: 14px;
  padding: 14px 18px;
  border-bottom: 1px solid var(--line);
}

.def-item:last-child {
  border-bottom: none;
}

.def-term {
  font-size: 14px;
  font-weight: 700;
  color: var(--text-main);
}

.def-desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--text-sub);
}

.boundary-grid {
  margin-top: 16px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 18px;
}

.boundary-col {
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
}

.boundary-heading {
  font-size: 15px;
  font-weight: 700;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}

.boundary-col .boundary-list {
  margin-top: 12px;
}

.boundary-note {
  margin-top: 14px;
  max-width: var(--prose);
  font-size: 13px;
  line-height: 1.7;
  color: var(--text-sub);
}

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

.relation-item {
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
}

.relation-heading {
  font-size: 15px;
  font-weight: 700;
}

.relation-desc {
  margin-top: 8px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--text-sub);
}

.relation-note {
  margin-top: 16px;
  max-width: var(--prose);
  font-size: 14px;
}

/* ============ inner: records ============ */

.records-intro {
  padding-top: 32px;
}

.records-rules {
  margin-top: 16px;
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.records-rule {
  display: flex;
  gap: 14px;
  padding: 12px 18px;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-sub);
}

.records-rule:last-child {
  border-bottom: none;
}

.records-rule-num {
  font-size: 13px;
  color: var(--accent);
  flex-shrink: 0;
}

.records-figure {
  margin-top: 24px;
}

.records-timeline-section {
  padding-top: 32px;
}

.records-timeline {
  margin-top: 20px;
  position: relative;
  padding-left: 0;
}

.records-month {
  position: relative;
  padding-left: 26px;
  margin-bottom: 26px;
}

.records-month:last-child {
  margin-bottom: 0;
}

.records-month::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 6px;
  bottom: -26px;
  width: 1px;
  background: var(--line);
}

.records-month:last-child::before {
  display: none;
}

.records-month-title {
  position: relative;
  font-size: 16px;
  font-weight: 700;
}

.records-month-title::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 8px;
  width: 11px;
  height: 11px;
  background: var(--card-bg);
  border: 2px solid var(--accent);
  border-radius: 50%;
}

.records-list {
  margin-top: 10px;
}

.records-item {
  display: grid;
  grid-template-columns: 110px 120px minmax(0, 1fr);
  gap: 6px 14px;
  align-items: baseline;
  padding: 10px 0;
  border-bottom: 1px dashed var(--line);
}

.records-item:last-child {
  border-bottom: none;
}

.records-date {
  font-size: 13px;
  color: var(--text-sub);
}

.records-type {
  font-size: 13px;
  color: var(--accent);
}

.records-desc {
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-sub);
}

.records-types {
  padding-top: 32px;
}

.records-types-layout {
  margin-top: 16px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 18px;
}

.records-types-col {
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
}

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

.records-type-list {
  margin: 12px 0 0;
}

.records-type-name {
  font-size: 14px;
  font-weight: 700;
  color: var(--text-main);
}

.records-type-desc {
  margin: 2px 0 10px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-sub);
}

.records-type-list dd:last-child {
  margin-bottom: 0;
}

.records-related {
  padding-top: 32px;
}

.records-scope-list {
  margin-top: 12px;
}

.records-scope-item {
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-sub);
  margin-bottom: 6px;
}

/* ============ 404 ============ */

.error-main {
  padding-top: 48px;
  padding-bottom: 64px;
}

.error-inner {
  max-width: var(--prose);
  margin: 0 auto;
  padding-left: 24px;
  padding-right: 24px;
  text-align: left;
}

.error-code {
  font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 40px;
  line-height: 1.2;
  color: var(--accent);
}

.error-title {
  margin-top: 8px;
  font-size: 28px;
  line-height: 1.35;
  font-weight: 700;
}

.error-desc {
  margin-top: 12px;
  color: var(--text-sub);
  line-height: 1.75;
}

.error-actions {
  margin-top: 20px;
  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 18px;
  font-size: 14px;
  font-weight: 600;
  border-radius: var(--radius);
  text-decoration: none;
}

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

.btn-primary:hover,
.btn-primary:focus-visible {
  background: #8f3623;
  color: #ffffff;
  text-decoration: none;
}

.btn-ghost {
  background: var(--card-bg);
  border: 1px solid var(--line);
  color: var(--text-main);
}

.btn-ghost:hover,
.btn-ghost:focus-visible {
  border-color: #b9c3ce;
  color: var(--accent);
  text-decoration: none;
}

.error-note {
  margin-top: 18px;
  font-size: 14px;
  color: var(--text-sub);
}

/* ============ footer ============ */

.site-footer {
  margin-top: 24px;
  background: var(--header-bg);
  color: #c8d2dd;
}

.footer-inner {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) repeat(3, minmax(0, 1fr));
  gap: 24px;
  padding-top: 32px;
  padding-bottom: 24px;
}

.footer-name {
  font-size: 16px;
  font-weight: 700;
  color: #ffffff;
}

.footer-desc {
  margin-top: 8px;
  font-size: 13px;
  line-height: 1.7;
  color: #93a2b3;
}

.footer-group-title {
  font-size: 14px;
  font-weight: 700;
  color: #ffffff;
}

.footer-toggle {
  display: block;
  width: 100%;
  padding: 0;
  background: none;
  border: none;
  color: #ffffff;
  font-size: 14px;
  font-weight: 700;
  font-family: inherit;
  text-align: left;
  cursor: default;
}

.footer-links {
  margin-top: 10px;
}

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

.footer-links a {
  color: #c8d2dd;
  font-size: 13px;
  text-decoration: none;
}

.footer-links a:hover,
.footer-links a:focus-visible {
  color: #ffffff;
  text-decoration: underline;
}

.footer-bottom {
  border-top: 1px solid #2c3846;
}

.footer-copy {
  max-width: var(--container);
  margin: 0 auto;
  padding: 14px 24px;
  font-size: 12px;
  color: #93a2b3;
}

/* ============ motion ============ */

.records-item,
.topic-entry,
.principle-item {
  transition: border-color 0.15s ease, background-color 0.15s ease;
}

@media (prefers-reduced-motion: no-preference) {
  .records-item {
    animation: none;
  }
}

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

@media (max-width: 960px) {
  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    background: var(--header-bg);
    border-bottom: 1px solid #0f1720;
    z-index: 50;
  }

  .header-inner {
    position: relative;
  }

  .nav-list {
    display: none;
    flex-direction: column;
    width: 100%;
    padding: 8px 16px 16px;
  }

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

  .nav-list a {
    min-height: 44px;
    padding: 0 8px;
    border-bottom: 1px solid #2c3846;
  }

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

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

  .channel-row,
  .channel-rows .channel-row {
    grid-template-columns: 48px minmax(0, 1fr);
    gap: 4px 12px;
  }

  .channel-row .channel-name {
    grid-column: 2;
  }

  .channel-row .channel-dir,
  .channel-row .channel-direction,
  .channel-row .channel-range,
  .channel-row .channel-scope {
    grid-column: 2;
  }

  .fields-columns,
  .boundary-grid,
  .records-types-layout {
    grid-template-columns: minmax(0, 1fr);
  }

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

  .site-index {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .footer-toggle {
    cursor: pointer;
  }

  .footer-group .footer-links {
    display: none;
  }

  .footer-group.is-open .footer-links {
    display: block;
  }

  .records-item {
    grid-template-columns: 110px minmax(0, 1fr);
  }

  .records-item .records-desc {
    grid-column: 1 / -1;
  }
}

@media (max-width: 640px) {
  .site-notice p,
  .header-inner,
  .footer-inner,
  .footer-copy,
  .site-main > .container,
  .inner-main > .container,
  .home-main > .home-section,
  .home-main > .home-hero,
  .inner-main > .breadcrumb,
  .inner-main > .page-header,
  .inner-main > .section,
  .inner-main > .records-intro,
  .inner-main > .records-timeline-section,
  .inner-main > .records-types,
  .inner-main > .records-related,
  .inner-main > figure,
  .error-inner {
    padding-left: 16px;
    padding-right: 16px;
  }

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

  .hero-tasks,
  .topic-cards,
  .principle-list,
  .step-list,
  .next-list,
  .relation-list {
    grid-template-columns: minmax(0, 1fr);
  }

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

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

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

  .page-role-item,
  .def-item,
  .topic-meta {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px;
  }

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

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

  .records-item .records-desc {
    grid-column: auto;
  }

  .scenario-table {
    min-width: 480px;
  }
}