:root {
  --bg: #f7f5f1;
  --ink: #1c1c1c;
  --ink-soft: #5c5c5c;
  --line: #d8d3cb;
  --line-strong: #b8b1a6;
  --accent: #c8452f;
  --accent-deep: #a5341f;
  --teal: #2f6f8f;
  --olive: #7a9a3d;
  --amber: #b07a2c;
  --paper: #ffffff;
  --paper-alt: #efece6;
  --radius: 6px;
  --radius-sm: 4px;
  --wrap: 1120px;
  --gap: 28px;
  --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans CJK SC", Arial, sans-serif;
  --font-mono: "SFMono-Regular", "JetBrains Mono", Consolas, "Courier New", monospace;
}

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

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

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

body {
  margin: 0;
  background-color: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.75;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
}

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

p {
  margin: 0;
}

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

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

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

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

figure {
  margin: 0;
}

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

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

button {
  font: inherit;
  color: inherit;
}

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

/* ==========================================================================
   layout — 全站骨架
   ========================================================================== */

.site-body {
  display: block;
  min-height: 100vh;
  background-color: var(--bg);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background-color: var(--paper);
  border-bottom: 2px solid var(--ink);
}

.header-inner {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 24px;
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 19px;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: 0;
  padding: 8px 0;
  min-height: 44px;
}

.brand::before {
  content: "";
  width: 12px;
  height: 12px;
  background-color: var(--accent);
  flex: none;
}

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

.site-nav {
  display: block;
}

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

.nav-list > li {
  display: block;
}

.nav-list a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 12px;
  font-size: 15px;
  color: var(--ink);
  border-bottom: 3px solid transparent;
}

.nav-list a:hover,
.nav-list a:focus-visible {
  color: var(--accent);
  text-decoration: none;
  border-bottom-color: var(--line-strong);
}

.nav-list a.is-current {
  color: var(--accent);
  font-weight: 700;
  border-bottom-color: var(--accent);
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  background-color: var(--paper);
  border: 2px solid var(--ink);
  border-radius: var(--radius-sm);
  cursor: pointer;
  position: relative;
  flex: none;
}

.nav-toggle::before {
  content: "";
  position: absolute;
  left: 11px;
  right: 11px;
  top: 13px;
  height: 2px;
  background-color: var(--ink);
  box-shadow: 0 7px 0 var(--ink), 0 14px 0 var(--ink);
}

.nav-toggle:hover {
  border-color: var(--accent);
}

.site-main {
  display: block;
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 24px 64px;
}

.inner-main {
  padding-top: 22px;
}

/* ==========================================================================
   components — 通用组件
   ========================================================================== */

.section-head {
  margin-bottom: 22px;
  padding-bottom: 14px;
  border-bottom: 2px solid var(--ink);
}

.section-title {
  font-size: 22px;
  letter-spacing: 0;
}

.section-desc {
  margin-top: 8px;
  max-width: 62ch;
  font-size: 14px;
  color: var(--ink-soft);
}

.section-intro,
.section-lead {
  margin-bottom: 20px;
  max-width: 68ch;
  font-size: 15px;
  color: var(--ink-soft);
}

.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  font-size: 13px;
  color: var(--ink-soft);
  padding: 4px 0;
}

.breadcrumb a {
  color: var(--ink-soft);
  min-height: 24px;
  display: inline-flex;
  align-items: center;
}

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

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

.breadcrumb-current {
  color: var(--ink);
  font-weight: 600;
}

.page-header {
  margin: 18px 0 34px;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--line);
}

.page-title {
  font-size: 30px;
  font-weight: 700;
  line-height: 1.3;
  color: var(--ink);
}

.page-description {
  margin-top: 12px;
  max-width: 72ch;
  font-size: 15px;
  color: var(--ink-soft);
}

.page-description a {
  color: var(--accent);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 20px;
  font-size: 15px;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: 2px solid var(--ink);
  text-decoration: none;
}

.btn:hover,
.btn:focus-visible {
  text-decoration: none;
}

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

.btn-primary:hover,
.btn-primary:focus-visible {
  background-color: var(--accent-deep);
  border-color: var(--accent-deep);
  color: #fff;
}

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

.btn-ghost:hover,
.btn-ghost:focus-visible {
  background-color: var(--ink);
  color: var(--paper);
}

/* 通用图片容器约束 */
.hero-figure,
.collection-cover,
.channel-figure,
.guide-figure,
.fields-figure,
.figure,
.record-figure {
  overflow: hidden;
  border-radius: var(--radius);
  background-color: var(--paper-alt);
}

.hero-figure img,
.collection-cover img,
.channel-figure img,
.guide-figure img,
.fields-figure img,
.figure img,
.record-figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

figcaption {
  font-size: 13px;
  color: var(--ink-soft);
}

/* ==========================================================================
   pages — 首页
   ========================================================================== */

.top-note {
  background-color: var(--ink);
  color: #efece6;
  font-size: 13px;
  line-height: 1.6;
  padding: 9px 24px;
  text-align: center;
}

.home-main {
  padding-top: 34px;
}

.home-hero {
  display: grid;
  grid-template-columns: 268px minmax(0, 1fr);
  gap: var(--gap);
  align-items: start;
  margin-bottom: 56px;
}

.hero-side {
  display: grid;
  gap: 18px;
  border-top: 3px solid var(--accent);
  padding-top: 16px;
}

.side-block {
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 16px 18px;
}

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

.side-channel-list,
.side-field-list {
  display: grid;
  gap: 2px;
}

.side-channel-list li,
.side-field-list li {
  border-bottom: 1px dashed var(--line);
}

.side-channel-list li:last-child,
.side-field-list li:last-child {
  border-bottom: 0;
}

.side-channel-list a,
.side-field-list a {
  display: flex;
  align-items: center;
  min-height: 40px;
  padding: 6px 0;
  font-size: 14px;
  color: var(--ink);
}

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

.hero-main {
  display: grid;
  gap: 22px;
}

.hero-figure {
  aspect-ratio: 16 / 8;
  border: 1px solid var(--line);
}

.hero-caption {
  margin-top: 10px;
  font-size: 13px;
  color: var(--ink-soft);
}

.hero-text {
  border-left: 4px solid var(--accent);
  padding-left: 18px;
}

.hero-kicker {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--teal);
  border: 1px solid var(--teal);
  border-radius: var(--radius-sm);
  padding: 2px 8px;
  margin-bottom: 12px;
}

.hero-title {
  font-size: 34px;
  line-height: 1.28;
  max-width: 20ch;
}

.hero-lead {
  margin-top: 14px;
  max-width: 60ch;
  font-size: 16px;
  color: var(--ink-soft);
}

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

.home-section {
  margin-bottom: 56px;
}

/* 频道方向索引 */
.channel-rows {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line);
}

.channel-row {
  display: grid;
  grid-template-columns: 62px minmax(0, 1fr) 132px;
  gap: 20px;
  align-items: start;
  padding: 20px 4px 20px 0;
  border-bottom: 1px solid var(--line);
  border-left: 3px solid transparent;
  transition: border-color 0.18s ease, background-color 0.18s ease;
}

.channel-row:hover {
  border-left-color: var(--accent);
  background-color: rgba(200, 69, 47, 0.04);
}

.channel-no {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 700;
  color: var(--accent);
  line-height: 1.4;
}

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

.channel-name {
  font-size: 17px;
  margin-bottom: 6px;
}

.channel-desc {
  font-size: 14px;
  color: var(--ink-soft);
  max-width: 60ch;
}

.channel-scope {
  margin-top: 8px;
  font-size: 13px;
  color: var(--ink-soft);
  padding-left: 12px;
  border-left: 2px solid var(--line-strong);
}

.channel-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 12px;
  font-size: 14px;
  font-weight: 600;
  color: var(--ink);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  text-align: center;
}

.channel-link:hover,
.channel-link:focus-visible {
  background-color: var(--ink);
  border-color: var(--ink);
  color: var(--paper);
  text-decoration: none;
}

/* 专题片单入口 */
.collection-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--gap);
}

.collection-card {
  display: flex;
  flex-direction: column;
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
  transition: transform 0.18s ease, border-color 0.18s ease;
}

.collection-card:hover {
  transform: translateY(-3px);
  border-color: var(--line-strong);
}

.collection-cover {
  aspect-ratio: 16 / 9;
  margin-bottom: 16px;
}

.collection-name {
  font-size: 18px;
  margin-bottom: 8px;
}

.collection-theme {
  font-size: 14px;
  color: var(--ink-soft);
}

.collection-note {
  margin-top: 10px;
  font-size: 13px;
  color: var(--ink-soft);
  padding-top: 10px;
  border-top: 1px dashed var(--line);
}

.collection-link {
  margin-top: 16px;
  align-self: flex-start;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 16px;
  font-size: 14px;
  font-weight: 600;
  color: var(--accent);
  border: 2px solid var(--accent);
  border-radius: var(--radius-sm);
}

.collection-link:hover,
.collection-link:focus-visible {
  background-color: var(--accent);
  color: #fff;
  text-decoration: none;
}

/* 浏览顺序四步 */
.browse-steps .step-list,
.guide-steps .step-list {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0;
  border-top: 1px solid var(--line);
}

.step-item {
  padding: 22px 18px 22px 0;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  min-height: 100%;
}

.step-item:last-child {
  border-right: 0;
}

.step-no {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  color: #fff;
  background-color: var(--ink);
  border-radius: var(--radius-sm);
  margin-bottom: 12px;
}

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

.step-note {
  font-size: 14px;
  color: var(--ink-soft);
}

.steps-more,
.records-more,
.field-more {
  margin-top: 20px;
  font-size: 14px;
}

.steps-more a,
.records-more a,
.field-more a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  font-weight: 600;
  color: var(--accent);
}

/* 字段说明与收录边界摘要 */
.field-columns {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  gap: var(--gap);
  align-items: start;
}

.field-col {
  min-width: 0;
}

.col-title {
  font-size: 17px;
  padding-bottom: 10px;
  margin-bottom: 14px;
  border-bottom: 2px solid var(--ink);
}

.field-table {
  font-size: 14px;
}

.field-caption,
.fields-caption {
  caption-side: top;
  text-align: left;
  font-size: 13px;
  color: var(--ink-soft);
  padding-bottom: 10px;
}

.field-table thead th {
  font-size: 13px;
  font-weight: 700;
  color: var(--ink);
  background-color: var(--paper-alt);
  padding: 10px 12px;
  border: 1px solid var(--line);
}

.field-table tbody th,
.field-table tbody td {
  padding: 10px 12px;
  border: 1px solid var(--line);
  font-size: 14px;
  color: var(--ink-soft);
}

.field-table tbody th {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--ink);
  white-space: nowrap;
  width: 34%;
}

.field-col .boundary-list {
  display: grid;
  gap: 10px;
}

.boundary-list li {
  position: relative;
  padding-left: 18px;
  font-size: 14px;
  color: var(--ink-soft);
}

.boundary-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 8px;
  height: 2px;
  background-color: var(--accent);
}

/* 整理记录速览 */
.records-groups {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--gap);
}

.record-group {
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-top: 3px solid var(--teal);
  border-radius: var(--radius);
  padding: 18px 16px;
}

.record-month {
  font-size: 16px;
  font-family: var(--font-mono);
  padding-bottom: 10px;
  margin-bottom: 12px;
  border-bottom: 1px solid var(--line);
}

.record-list {
  display: grid;
  gap: 14px;
}

.record-item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 10px;
}

.record-item time,
.record-date {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--teal);
}

.record-scope {
  font-size: 12px;
  color: var(--ink-soft);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  padding: 0 6px;
  justify-self: start;
}

.record-text {
  grid-column: 1 / -1;
  font-size: 14px;
  color: var(--ink-soft);
}

/* 站内栏目索引 */
.index-grid {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 1px;
  background-color: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.index-cell {
  background-color: var(--paper);
}

.index-cell a {
  display: flex;
  flex-direction: column;
  gap: 8px;
  height: 100%;
  min-height: 108px;
  padding: 16px 14px;
  color: var(--ink);
}

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

.index-name {
  font-size: 15px;
  font-weight: 700;
}

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

/* ==========================================================================
   pages — 频道分类
   ========================================================================== */

.channel-overview {
  margin-bottom: 48px;
}

.channel-list {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line);
}

.channel-overview .channel-row {
  display: block;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
  border-left: 0;
}

.channel-overview .channel-row:hover {
  background-color: transparent;
}

.channel-item {
  display: grid;
  grid-template-columns: 62px minmax(0, 1fr) 200px;
  gap: 20px;
  align-items: start;
}

.channel-overview .channel-no {
  font-size: 20px;
}

.channel-cover {
  margin: 0;
  font-size: 13px;
  color: var(--ink-soft);
  border-left: 3px solid var(--olive);
  padding-left: 12px;
}

.channel-cover-label {
  display: block;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 4px;
}

.channel-figure {
  margin-top: 30px;
  aspect-ratio: 21 / 8;
  border: 1px solid var(--line);
}

.channel-figure figcaption {
  margin-top: 10px;
}

.channel-divide,
.channel-boundary {
  margin-bottom: 48px;
}

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

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

.divide-name {
  font-size: 16px;
  padding-bottom: 10px;
  margin-bottom: 12px;
  border-bottom: 2px solid var(--ink);
}

.divide-text {
  font-size: 14px;
  color: var(--ink-soft);
}

.divide-note {
  margin-top: 20px;
  font-size: 14px;
}

.divide-note a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  font-weight: 600;
}

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

.boundary-col {
  min-width: 0;
}

.boundary-name {
  font-size: 17px;
  padding-bottom: 10px;
  margin-bottom: 14px;
  border-bottom: 2px solid var(--ink);
}

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

.boundary-note {
  margin-top: 22px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  font-size: 14px;
}

.boundary-note a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  font-weight: 600;
}

/* ==========================================================================
   pages — 专题片单
   ========================================================================== */

.section {
  margin-bottom: 48px;
}

.section-collection-theme h2,
.section-collection-order h2,
.section-collection-status h2,
.fields-table-section h2,
.fields-rule-aside h2,
.boundary-section h2 {
  font-size: 22px;
  padding-bottom: 12px;
  margin-bottom: 18px;
  border-bottom: 2px solid var(--ink);
}

.section-collection-theme p {
  max-width: 72ch;
  margin-bottom: 14px;
  font-size: 15px;
  color: var(--ink-soft);
}

.figure-collection-cover {
  margin-top: 22px;
  aspect-ratio: 21 / 9;
  border: 1px solid var(--line);
}

.figure-collection-cover figcaption {
  margin-top: 10px;
}

.order-list {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line);
  counter-reset: order;
}

.order-item {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr);
  gap: 18px;
  align-items: start;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.order-item::before {
  counter-increment: order;
  content: counter(order, decimal-leading-zero);
  font-family: var(--font-mono);
  font-size: 18px;
  font-weight: 700;
  color: var(--accent);
  line-height: 1.5;
}

.order-item h3 {
  font-size: 17px;
  margin-bottom: 6px;
}

.order-item p {
  font-size: 14px;
  color: var(--ink-soft);
  max-width: 66ch;
}

.status-list {
  display: grid;
  gap: 12px;
  margin-bottom: 20px;
}

.status-item {
  font-size: 14px;
  color: var(--ink-soft);
  padding: 12px 14px;
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-left: 3px solid var(--amber);
  border-radius: var(--radius-sm);
}

.status-item strong {
  color: var(--ink);
  margin-right: 6px;
}

.section-collection-status p:last-child {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  font-size: 14px;
}

.section-collection-status p:last-child a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  font-weight: 600;
}

/* ==========================================================================
   pages — 浏览指引
   ========================================================================== */

.guide-steps,
.guide-verify,
.guide-faq,
.guide-next {
  margin-bottom: 48px;
}

.guide-steps .step-list {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.guide-steps .step-item {
  padding: 22px 18px;
}

.guide-steps .step-item:first-child {
  padding-left: 0;
}

.guide-steps .step-index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  color: #fff;
  background-color: var(--accent);
  border-radius: var(--radius-sm);
  margin-bottom: 12px;
}

.guide-steps .step-name {
  font-size: 16px;
  margin-bottom: 8px;
}

.guide-steps .step-desc {
  font-size: 14px;
  color: var(--ink-soft);
}

.guide-steps .step-check {
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px dashed var(--line);
  font-size: 13px;
  color: var(--ink-soft);
}

.guide-figure {
  aspect-ratio: 21 / 8;
  border: 1px solid var(--line);
  margin-bottom: 10px;
}

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

.verify-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px var(--gap);
}

.verify-item {
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 16px;
}

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

.verify-desc {
  font-size: 14px;
  color: var(--ink-soft);
}

.faq-item {
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
}

.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 52px;
  padding: 14px 18px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
}

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

.faq-question::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 20px;
  line-height: 1;
  color: var(--accent);
  flex: none;
}

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

.faq-question:hover {
  background-color: var(--paper-alt);
}

.faq-answer {
  padding: 0 18px 18px;
  font-size: 14px;
  color: var(--ink-soft);
  border-top: 1px solid var(--line);
  padding-top: 14px;
}

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

.next-item a {
  display: flex;
  align-items: center;
  min-height: 56px;
  padding: 14px 16px;
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius-sm);
}

.next-item a:hover,
.next-item a:focus-visible {
  background-color: var(--paper-alt);
  color: var(--accent);
  text-decoration: none;
}

/* ==========================================================================
   pages — 字段说明
   ========================================================================== */

.fields-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(260px, 0.85fr);
  gap: 40px;
  align-items: start;
  margin-bottom: 48px;
}

.fields-table-section {
  min-width: 0;
}

.fields-figure {
  aspect-ratio: 16 / 7;
  border: 1px solid var(--line);
  margin-bottom: 10px;
}

.fields-figure figcaption {
  margin-bottom: 22px;
}

.fields-table {
  font-size: 14px;
}

.fields-table thead th {
  font-size: 13px;
  font-weight: 700;
  background-color: var(--paper-alt);
  padding: 10px 12px;
  border: 1px solid var(--line);
}

.fields-table tbody th,
.fields-table tbody td {
  padding: 12px;
  border: 1px solid var(--line);
  font-size: 14px;
  color: var(--ink-soft);
}

.fields-table tbody th {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--ink);
  white-space: nowrap;
  width: 30%;
  background-color: var(--paper);
}

.fields-table tbody td {
  background-color: var(--paper);
}

.fields-rule-aside {
  min-width: 0;
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-top: 3px solid var(--teal);
  border-radius: var(--radius);
  padding: 20px 18px;
}

.fields-rule-aside p {
  font-size: 14px;
  color: var(--ink-soft);
  margin-bottom: 12px;
}

.fields-rule-aside p:last-child {
  margin-bottom: 0;
}

.boundary-section {
  margin-bottom: 48px;
}

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

.boundary-grid .boundary-col h3 {
  font-size: 17px;
  padding-bottom: 10px;
  margin-bottom: 14px;
  border-bottom: 2px solid var(--ink);
}

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

.boundary-section .boundary-note {
  margin-top: 22px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  font-size: 14px;
}

.boundary-section .boundary-note a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  font-weight: 600;
}

/* ==========================================================================
   pages — 整理记录
   ========================================================================== */

.record-figure {
  aspect-ratio: 21 / 8;
  border: 1px solid var(--line);
  margin-bottom: 10px;
}

.record-figure figcaption {
  margin-bottom: 34px;
}

.records-section,
.scope-section,
.method-section {
  margin-bottom: 48px;
}

.records-section > .section-title,
.scope-section > .section-title,
.method-section > .section-title {
  font-size: 22px;
  padding-bottom: 12px;
  margin-bottom: 16px;
  border-bottom: 2px solid var(--ink);
}

.record-month {
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px 18px;
  margin-bottom: 20px;
  scroll-margin-top: 90px;
}

.records-section .month-title {
  font-family: var(--font-mono);
  font-size: 17px;
  padding-bottom: 12px;
  margin-bottom: 16px;
  border-bottom: 1px solid var(--line);
}

.records-section .record-list {
  display: grid;
  gap: 16px;
}

.records-section .record-item {
  display: grid;
  grid-template-columns: auto auto minmax(0, 1fr);
  gap: 6px 12px;
  align-items: baseline;
  padding-bottom: 14px;
  border-bottom: 1px dashed var(--line);
}

.records-section .record-item:last-child {
  padding-bottom: 0;
  border-bottom: 0;
}

.records-section .record-text {
  grid-column: 1 / -1;
  font-size: 14px;
  color: var(--ink-soft);
}

.scope-list {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line);
  margin-bottom: 18px;
}

.scope-term {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
  padding-top: 16px;
}

.scope-desc {
  margin: 0 0 16px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
  color: var(--ink-soft);
  max-width: 72ch;
}

.scope-note-text {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  font-size: 14px;
}

.scope-note-text a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  font-weight: 600;
}

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

.method-item {
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-top: 3px solid var(--olive);
  border-radius: var(--radius);
  padding: 18px 16px;
}

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

.method-text {
  font-size: 14px;
  color: var(--ink-soft);
}

.method-note {
  margin-top: 20px;
  font-size: 14px;
}

.method-note a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  font-weight: 600;
}

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

.error-main {
  padding-top: 48px;
  padding-bottom: 72px;
}

.error-block {
  border-left: 4px solid var(--accent);
  padding-left: 22px;
  margin-bottom: 48px;
}

.error-code {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 10px;
}

.error-main h1 {
  font-size: 30px;
  margin-bottom: 14px;
}

.error-text {
  max-width: 60ch;
  font-size: 15px;
  color: var(--ink-soft);
}

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

.error-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 22px;
  font-size: 15px;
  font-weight: 600;
  color: #fff;
  background-color: var(--accent);
  border: 2px solid var(--accent);
  border-radius: var(--radius-sm);
}

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

.error-links h2 {
  font-size: 20px;
  padding-bottom: 12px;
  margin-bottom: 18px;
  border-bottom: 2px solid var(--ink);
}

.error-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.error-list a {
  display: flex;
  align-items: center;
  min-height: 52px;
  padding: 12px 16px;
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
  background-color: var(--paper);
  border: 1px solid var(--line);
  border-left: 3px solid var(--teal);
  border-radius: var(--radius-sm);
}

.error-list a:hover,
.error-list a:focus-visible {
  background-color: var(--paper-alt);
  color: var(--accent);
  text-decoration: none;
}

/* ==========================================================================
   layout — 页脚
   ========================================================================== */

.site-footer {
  background-color: var(--ink);
  color: #d9d4cc;
  border-top: 3px solid var(--accent);
  margin-top: 40px;
}

.footer-inner {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 46px 24px 32px;
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) repeat(4, minmax(0, 1fr));
  gap: 32px 24px;
  align-items: start;
}

.footer-brand {
  min-width: 0;
}

.footer-logo {
  font-size: 18px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 12px;
}

.footer-about {
  font-size: 13px;
  line-height: 1.75;
  color: #a8a29a;
  max-width: 34ch;
}

.footer-col {
  min-width: 0;
}

.footer-title {
  font-size: 14px;
  font-weight: 700;
  color: #fff;
  padding-bottom: 10px;
  margin-bottom: 12px;
  border-bottom: 1px solid #3a3a3a;
}

.footer-list {
  display: grid;
  gap: 2px;
}

.footer-list a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  font-size: 13px;
  color: #c9c4bc;
}

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

.footer-copy {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 16px 24px 26px;
  font-size: 12px;
  color: #8b857d;
  border-top: 1px solid #3a3a3a;
}

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

@media (max-width: 1024px) {
  .home-hero {
    grid-template-columns: 236px minmax(0, 1fr);
  }

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

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

  .footer-brand {
    grid-column: 1 / -1;
  }
}

@media (max-width: 900px) {
  .home-hero {
    grid-template-columns: minmax(0, 1fr);
  }

  .hero-side {
    order: 2;
  }

  .hero-main {
    order: 1;
  }

  .browse-steps .step-list,
  .guide-steps .step-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .step-item:nth-child(2n) {
    border-right: 0;
  }

  .field-columns,
  .fields-layout,
  .records-groups,
  .divide-grid,
  .method-list,
  .next-list,
  .error-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .fields-rule-aside {
    order: 2;
  }

  .channel-item {
    grid-template-columns: 52px minmax(0, 1fr);
  }

  .channel-cover {
    grid-column: 2 / -1;
    margin-top: 8px;
  }
}

@media (max-width: 760px) {
  .header-inner {
    padding: 0 16px;
    flex-wrap: wrap;
    min-height: 60px;
  }

  .nav-toggle {
    display: block;
  }

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

  .nav-list {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 0 12px;
    border-top: 1px solid var(--line);
  }

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

  .nav-list a {
    min-height: 48px;
    padding: 0 6px;
    border-bottom: 0;
    border-left: 3px solid transparent;
    padding-left: 12px;
  }

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

  .nav-list a:hover,
  .nav-list a:focus-visible {
    border-bottom-color: transparent;
    border-left-color: var(--line-strong);
  }

  .top-note {
    padding: 9px 16px;
    text-align: left;
  }

  .site-main {
    padding: 0 16px 48px;
  }

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

  .hero-title {
    font-size: 26px;
    max-width: none;
  }

  .hero-text {
    padding-left: 14px;
  }

  .page-title {
    font-size: 24px;
  }

  .page-header {
    margin: 14px 0 26px;
    padding-bottom: 18px;
  }

  .home-section,
  .section,
  .channel-overview,
  .channel-divide,
  .channel-boundary,
  .fields-layout,
  .boundary-section,
  .records-section,
  .scope-section,
  .method-section,
  .guide-steps,
  .guide-verify,
  .guide-faq,
  .guide-next {
    margin-bottom: 36px;
  }

  .channel-row {
    grid-template-columns: 46px minmax(0, 1fr);
    gap: 12px;
  }

  .channel-link {
    grid-column: 2 / -1;
    justify-self: start;
    margin-top: 6px;
  }

  .collection-grid,
  .field-columns,
  .fields-layout,
  .records-groups,
  .divide-grid,
  .boundary-columns,
  .boundary-grid,
  .verify-list,
  .method-list,
  .next-list,
  .error-list,
  .index-grid,
  .footer-inner {
    grid-template-columns: minmax(0, 1fr);
  }

  .footer-brand {
    grid-column: auto;
  }

  .footer-inner {
    padding: 34px 16px 24px;
    gap: 26px;
  }

  .footer-copy {
    padding: 14px 16px 22px;
  }

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

  .index-cell a {
    min-height: 0;
  }

  .channel-figure,
  .guide-figure,
  .record-figure,
  .figure-collection-cover {
    aspect-ratio: 16 / 9;
  }

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

@media (max-width: 560px) {
  .browse-steps .step-list,
  .guide-steps .step-list {
    grid-template-columns: minmax(0, 1fr);
  }

  .step-item,
  .guide-steps .step-item,
  .guide-steps .step-item:first-child {
    border-right: 0;
    padding: 18px 0;
  }

  .order-item {
    grid-template-columns: 40px minmax(0, 1fr);
    gap: 12px;
  }

  .hero-actions {
    gap: 10px;
  }

  .btn {
    width: 100%;
  }

  .hero-title {
    font-size: 24px;
  }

  .section-title,
  .section-collection-theme h2,
  .section-collection-order h2,
  .section-collection-status h2,
  .fields-table-section h2,
  .fields-rule-aside h2,
  .boundary-section h2,
  .records-section > .section-title,
  .scope-section > .section-title,
  .method-section > .section-title {
    font-size: 20px;
  }

  .field-table tbody th,
  .fields-table tbody th {
    white-space: normal;
    width: 40%;
  }

  .error-main h1 {
    font-size: 24px;
  }
}