:root {
  --bg: #ffffff;
  --text: #1f2328;
  --muted: #57606a;
  --line: #d8dee4;
  --accent: #2f5d8c;
  --accent-soft: #eef3f8;
  --accent-deep: #24486d;
  --surface: #f7f9fb;
  --radius: 6px;
  --radius-sm: 4px;
  --shell: 1120px;
  --gap: 24px;
  --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans CJK SC", system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
}

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

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  letter-spacing: 0;
}

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

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

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

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

p {
  margin: 0;
}

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

dl, dd, dt, figure, figcaption {
  margin: 0;
}

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

button {
  font-family: inherit;
  cursor: pointer;
}

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

/* ===== base: 通用工具与语义 ===== */

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

.skip-link {
  position: absolute;
  left: 16px;
  top: -48px;
  z-index: 40;
  padding: 8px 14px;
  background: var(--accent);
  color: #fff;
  border-radius: var(--radius-sm);
  transition: top 0.15s ease;
}

.skip-link:focus {
  top: 12px;
  color: #fff;
  text-decoration: none;
}

.text-link {
  color: var(--accent);
  font-weight: 600;
  border-bottom: 1px solid rgba(47, 93, 140, 0.35);
  padding-bottom: 1px;
}

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

/* ===== layout: 全站骨架 ===== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  background: #fff;
  border-bottom: 1px solid var(--line);
}

.header-inner {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 12px 24px;
  display: flex;
  align-items: center;
  gap: 20px;
  min-height: 64px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
  color: var(--text);
}

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

.brand-mark {
  width: 36px;
  height: 36px;
  object-fit: contain;
  border-radius: var(--radius-sm);
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.25;
}

.brand-name {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: 0.5px;
}

.brand-slogan {
  font-size: 12px;
  color: var(--muted);
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: #fff;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  margin-left: auto;
}

.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--text);
  border-radius: 1px;
}

.site-nav {
  margin-left: auto;
}

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

.nav-link {
  display: block;
  padding: 8px 14px;
  font-size: 15px;
  color: var(--text);
  border-radius: var(--radius-sm);
  border-bottom: 2px solid transparent;
  transition: background 0.15s ease, color 0.15s ease;
}

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

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

.site-main {
  display: block;
}

.inner-main {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 24px 24px 64px;
}

.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 20px;
}

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

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

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

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

.page-header {
  padding-bottom: 20px;
  margin-bottom: 32px;
  border-bottom: 1px solid var(--line);
}

.page-title {
  font-size: 32px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 12px;
}

.page-description,
.page-lead {
  font-size: 16px;
  color: var(--muted);
  max-width: 780px;
}

.page-lead {
  margin-top: 10px;
}

.site-footer {
  border-top: 1px solid var(--line);
  background: var(--surface);
  margin-top: 40px;
}

.footer-inner {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 40px 24px 24px;
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1fr;
  gap: 32px;
}

.footer-brand-name {
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 8px;
}

.footer-brand-desc {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.65;
}

.footer-group-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 12px;
  letter-spacing: 0.5px;
}

.footer-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

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

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

.footer-bottom {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 16px 24px 28px;
  border-top: 1px solid var(--line);
}

.footer-copy {
  font-size: 13px;
  color: var(--muted);
}

/* ===== components: 通用标题、栏目容器 ===== */

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

.section-desc,
.section-intro,
.section-note {
  font-size: 15px;
  color: var(--muted);
  margin-top: 8px;
  max-width: 820px;
}

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

.column-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
  padding-bottom: 8px;
  border-bottom: 2px solid var(--accent);
  display: inline-block;
}

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

.column-more {
  margin-top: 16px;
  font-size: 14px;
}

/* ===== pages: 首页 ===== */

.fact-bar {
  background: var(--accent-soft);
  border-bottom: 1px solid var(--line);
}

.fact-bar-text {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 10px 24px;
  font-size: 14px;
  color: var(--accent-deep);
}

.home-main {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 0 24px 64px;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
  gap: 40px;
  align-items: start;
  padding: 48px 0 40px;
  border-bottom: 1px solid var(--line);
}

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

.hero-title {
  font-size: 34px;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 16px;
}

.hero-lead {
  font-size: 16px;
  color: var(--muted);
  margin-bottom: 24px;
}

.hero-paths {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.hero-path {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.hero-path:hover {
  border-color: var(--accent);
  box-shadow: 0 2px 10px rgba(47, 93, 140, 0.08);
}

.hero-path-link {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 12px 16px;
  color: var(--text);
}

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

.hero-path-name {
  font-size: 15px;
  font-weight: 700;
  color: var(--accent);
}

.hero-path-desc {
  font-size: 13px;
  color: var(--muted);
}

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

.hero-image {
  width: 100%;
  height: auto;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--line);
}

.hero-caption {
  font-size: 13px;
  color: var(--muted);
  margin-top: 10px;
  line-height: 1.6;
}

.topic-overview {
  padding: 48px 0;
  border-bottom: 1px solid var(--line);
}

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

.topic-card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px 18px;
  background: #fff;
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: border-color 0.15s ease, transform 0.15s ease;
}

.topic-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.topic-name {
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
}

.topic-desc {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.65;
}

.topic-rep {
  font-size: 13px;
  color: var(--muted);
  margin-top: auto;
}

.cover-updates {
  padding: 48px 0;
  border-bottom: 1px solid var(--line);
}

.cover-updates-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
  gap: 40px;
  margin-top: 24px;
}

.cover-column {
  min-width: 0;
}

.cover-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 18px;
}

.cover-item {
  min-width: 0;
}

.cover-link {
  display: block;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: #fff;
  color: var(--text);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.cover-link:hover,
.cover-link:focus-visible {
  border-color: var(--accent);
  box-shadow: 0 3px 12px rgba(31, 35, 40, 0.08);
  text-decoration: none;
}

.cover-image {
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  background: var(--surface);
}

.cover-name {
  display: block;
  font-size: 14px;
  font-weight: 700;
  padding: 10px 12px 4px;
  color: var(--text);
}

.cover-tag {
  display: block;
  font-size: 12px;
  color: var(--muted);
  padding: 0 12px 12px;
}

.updates-column {
  min-width: 0;
}

.update-list {
  margin-top: 18px;
  border-top: 1px solid var(--line);
}

.update-row {
  display: grid;
  grid-template-columns: 88px minmax(0, 1fr) auto;
  grid-template-areas:
    "date name topic"
    "date range range";
  gap: 4px 12px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.update-date {
  grid-area: date;
  font-size: 13px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

.update-name {
  grid-area: name;
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
}

.update-topic {
  grid-area: topic;
  font-size: 12px;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  align-self: start;
  white-space: nowrap;
}

.update-range {
  grid-area: range;
  font-size: 13px;
  color: var(--muted);
}

.ranking-fields {
  padding: 48px 0;
  border-bottom: 1px solid var(--line);
}

.ranking-fields-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
  gap: 40px;
  margin-top: 24px;
}

.ranking-column {
  min-width: 0;
}

.rank-list {
  margin-top: 18px;
  border-top: 1px solid var(--line);
}

.rank-row {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr) auto;
  grid-template-areas:
    "index name topic"
    "index note note";
  gap: 4px 12px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.rank-index {
  grid-area: index;
  font-size: 15px;
  font-weight: 700;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

.rank-name {
  grid-area: name;
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
}

.rank-topic {
  grid-area: topic;
  font-size: 12px;
  color: var(--muted);
  align-self: start;
  white-space: nowrap;
}

.rank-note {
  grid-area: note;
  font-size: 13px;
  color: var(--muted);
}

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

.field-brief {
  margin-top: 18px;
  border-top: 1px solid var(--line);
}

.field-name {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  padding-top: 12px;
}

.field-value {
  font-size: 13px;
  color: var(--muted);
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line);
  line-height: 1.65;
}

.site-index {
  padding: 48px 0 0;
}

.index-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 16px;
}

.index-cell {
  min-width: 0;
}

.index-link {
  display: flex;
  flex-direction: column;
  gap: 6px;
  height: 100%;
  padding: 18px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  color: var(--text);
  transition: border-color 0.15s ease, background 0.15s ease;
}

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

.index-name {
  font-size: 15px;
  font-weight: 700;
  color: var(--accent);
}

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

/* ===== pages: 题材分类 ===== */

.topic-groups {
  margin-bottom: 48px;
}

.topic-group-list {
  display: flex;
  flex-direction: column;
  gap: 24px;
  margin-top: 24px;
}

.topic-group {
  display: grid;
  grid-template-columns: minmax(0, 280px) minmax(0, 1fr);
  gap: 28px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
}

.topic-group-media {
  min-width: 0;
}

.topic-figure {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.topic-figure img {
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border-radius: var(--radius-sm);
  border: 1px solid var(--line);
}

.topic-figure-caption {
  font-size: 12px;
  color: var(--muted);
  line-height: 1.55;
}

.topic-group-body {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.topic-group-name {
  font-size: 19px;
  font-weight: 700;
  color: var(--text);
}

.topic-group-trait {
  font-size: 15px;
  color: var(--muted);
  line-height: 1.7;
}

.topic-group-meta {
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: 6px 16px;
  margin-top: 4px;
  padding-top: 14px;
  border-top: 1px dashed var(--line);
}

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

.topic-meta-value {
  font-size: 13px;
  color: var(--muted);
  line-height: 1.65;
}

.topic-compare {
  margin-bottom: 48px;
}

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

.compare-column {
  min-width: 0;
  padding: 22px 22px 24px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.compare-column-title {
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}

.compare-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.compare-item {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.65;
  padding-left: 14px;
  position: relative;
}

.compare-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--accent);
}

.compare-key {
  color: var(--text);
  font-weight: 700;
}

.related-categories {
  margin-bottom: 8px;
}

.related-list {
  display: flex;
  flex-direction: column;
  border-top: 1px solid var(--line);
  margin-top: 20px;
}

.related-item {
  display: grid;
  grid-template-columns: 180px minmax(0, 1fr) auto;
  gap: 16px;
  align-items: center;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
}

.related-name {
  font-weight: 700;
  color: var(--text);
}

.related-desc {
  color: var(--muted);
  line-height: 1.6;
}

.related-link {
  font-weight: 600;
  white-space: nowrap;
}

/* ===== pages: 最近更新 ===== */

.view-tabs {
  margin-bottom: 44px;
}

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

.view-tab-card {
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 18px 18px 20px;
  background: #fff;
}

.view-tab-name {
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 8px;
}

.view-tab-desc {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.65;
}

.update-list {
  margin-bottom: 44px;
}

.update-figure {
  margin: 20px 0 28px;
}

.update-figure img {
  width: 100%;
  height: auto;
  max-height: 320px;
  aspect-ratio: 16 / 7;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--line);
}

.update-figure-caption {
  font-size: 13px;
  color: var(--muted);
  margin-top: 8px;
}

.update-group {
  margin-bottom: 28px;
}

.update-group-date {
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
  padding-bottom: 8px;
  border-bottom: 2px solid var(--accent);
  display: inline-block;
  margin-bottom: 8px;
  font-variant-numeric: tabular-nums;
}

.update-items {
  border-top: 1px solid var(--line);
}

.update-item {
  display: grid;
  grid-template-columns: 84px minmax(0, 1fr) auto;
  grid-template-areas:
    "type name topic"
    "type range range"
    "note note note";
  gap: 4px 14px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.update-type {
  grid-area: type;
  font-size: 12px;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  align-self: start;
  text-align: center;
  white-space: nowrap;
}

.update-type-new {
  color: #1d5c3a;
  background: #e4f3ea;
}

.update-type-adjust {
  color: #8a5a12;
  background: #faf0dc;
}

.update-type-history {
  color: var(--muted);
  background: var(--surface);
  border: 1px solid var(--line);
}

.update-item .update-name {
  grid-area: name;
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
}

.update-item .update-topic {
  grid-area: topic;
  font-size: 12px;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  align-self: start;
  white-space: nowrap;
}

.update-item .update-range {
  grid-area: range;
  font-size: 13px;
  color: var(--muted);
}

.update-note {
  grid-area: note;
  font-size: 13px;
  color: var(--muted);
  line-height: 1.65;
  margin-top: 2px;
}

.field-note {
  margin-bottom: 44px;
}

.field-note-list {
  margin-top: 20px;
  border-top: 1px solid var(--line);
}

.field-note-term {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  padding-top: 14px;
}

.field-note-desc {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.65;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}

.field-note-more {
  margin-top: 16px;
  font-size: 14px;
}

.related-links {
  margin-bottom: 8px;
}

.related-links .related-item {
  display: block;
  padding: 14px 0;
}

.related-links .related-item .related-link {
  font-size: 15px;
}

/* ===== pages: 人气榜单 ===== */

.page-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.9fr) minmax(0, 1fr);
  gap: 40px;
  align-items: start;
}

.ranking-section {
  min-width: 0;
}

.ranking-list {
  margin-top: 20px;
  border-top: 1px solid var(--line);
}

.ranking-item {
  display: grid;
  grid-template-columns: 48px 84px minmax(0, 1fr);
  gap: 18px;
  align-items: start;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.ranking-position {
  font-size: 20px;
  font-weight: 700;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
  line-height: 1.3;
  padding-top: 2px;
}

.ranking-cover {
  margin: 0;
}

.ranking-cover img {
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border-radius: var(--radius-sm);
  border: 1px solid var(--line);
}

.ranking-body {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.ranking-name {
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
}

.ranking-topic {
  font-size: 12px;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  align-self: flex-start;
}

.ranking-reason {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
}

.rank-note {
  min-width: 0;
  padding: 24px 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.rank-note-list {
  margin-top: 18px;
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.rank-note-item {
  padding-bottom: 16px;
  border-bottom: 1px solid var(--line);
}

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

.rank-note-heading {
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 6px;
}

.rank-note-item p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
}

.rank-relation {
  margin-top: 44px;
  padding-top: 32px;
  border-top: 1px solid var(--line);
}

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

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

.relation-heading {
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 8px;
}

.relation-item p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
}

/* ===== pages: 条目字段说明 ===== */

.section {
  margin-bottom: 48px;
}

.section-field-visual .field-figure {
  margin-top: 20px;
}

.field-figure img {
  width: 100%;
  height: auto;
  max-height: 360px;
  aspect-ratio: 16 / 7;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--line);
}

.field-figure-caption {
  font-size: 13px;
  color: var(--muted);
  margin-top: 10px;
  line-height: 1.6;
}

.table-wrap {
  overflow-x: auto;
  margin-top: 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.field-table {
  min-width: 640px;
}

.field-table-caption {
  caption-side: top;
  text-align: left;
  font-size: 13px;
  color: var(--muted);
  padding: 12px 16px;
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}

.field-table thead th {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  text-align: left;
  padding: 12px 16px;
  background: var(--accent-soft);
  border-bottom: 1px solid var(--line);
  white-space: nowrap;
}

.field-table tbody th {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  text-align: left;
  padding: 14px 16px;
  border-bottom: 1px solid var(--line);
  white-space: nowrap;
  vertical-align: top;
}

.field-table tbody td {
  font-size: 14px;
  color: var(--muted);
  padding: 14px 16px;
  border-bottom: 1px solid var(--line);
  line-height: 1.7;
  vertical-align: top;
}

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

.field-table-note {
  margin-top: 14px;
  font-size: 14px;
  color: var(--muted);
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
}

.boundary-columns {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
  margin-top: 20px;
}

.boundary-col {
  min-width: 0;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.boundary-col-in {
  background: #f4f9f6;
  border-color: #cfe4d8;
}

.boundary-col-out {
  background: #fbf6f4;
  border-color: #e8d6cf;
}

.boundary-subtitle {
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}

.boundary-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.boundary-list li {
  position: relative;
  padding-left: 18px;
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
}

.boundary-col-in .boundary-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 8px;
  height: 4px;
  border-left: 2px solid #2f7a52;
  border-bottom: 2px solid #2f7a52;
  transform: rotate(-45deg);
}

.boundary-col-out .boundary-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 11px;
  width: 10px;
  height: 2px;
  background: #b0563c;
}

.path-list {
  margin-top: 20px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  counter-reset: path;
}

.path-item {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 16px;
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
}

.path-index {
  grid-row: span 2;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  font-size: 15px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

.path-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
}

.path-text {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
}

.faq-list {
  margin-top: 20px;
  border-top: 1px solid var(--line);
}

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

.faq-question {
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
  padding: 16px 34px 16px 0;
  position: relative;
  cursor: pointer;
  list-style: none;
}

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

.faq-question::after {
  content: "";
  position: absolute;
  right: 8px;
  top: 24px;
  width: 9px;
  height: 9px;
  border-right: 2px solid var(--accent);
  border-bottom: 2px solid var(--accent);
  transform: rotate(45deg);
  transition: transform 0.2s ease;
}

.faq-item[open] .faq-question::after {
  transform: rotate(-135deg);
  top: 26px;
}

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

.faq-answer {
  padding: 0 0 18px;
}

.faq-answer p {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.75;
  max-width: 860px;
}

/* ===== pages: 404 ===== */

.error-main {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 72px 24px 88px;
}

.error-block {
  max-width: 720px;
  margin: 0 auto;
  text-align: center;
}

.error-code {
  font-size: 56px;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
  letter-spacing: 2px;
  margin-bottom: 12px;
}

.error-title {
  font-size: 26px;
  font-weight: 700;
  margin-bottom: 14px;
}

.error-text {
  font-size: 15px;
  color: var(--muted);
  margin-bottom: 28px;
}

.error-paths {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-bottom: 28px;
}

.error-path-link {
  display: block;
  padding: 10px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  font-size: 14px;
  color: var(--text);
  background: #fff;
  transition: border-color 0.15s ease, color 0.15s ease;
}

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

.error-home-btn {
  display: inline-block;
  padding: 12px 28px;
  background: var(--accent);
  color: #fff;
  font-size: 15px;
  font-weight: 700;
  border-radius: var(--radius);
  transition: background 0.15s ease;
}

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

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

@media (max-width: 1024px) {
  .topic-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

@media (max-width: 900px) {
  .hero {
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
    padding: 36px 0 32px;
  }

  .cover-updates-layout,
  .ranking-fields-layout {
    grid-template-columns: minmax(0, 1fr);
    gap: 36px;
  }

  .page-layout {
    grid-template-columns: minmax(0, 1fr);
    gap: 36px;
  }

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

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

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

  .topic-figure img {
    aspect-ratio: 16 / 9;
    max-height: 260px;
  }
}

@media (max-width: 768px) {
  .header-inner {
    flex-wrap: wrap;
    padding: 10px 18px;
    gap: 12px;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    width: 100%;
    margin-left: 0;
    order: 3;
  }

  .nav-list {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    padding: 8px 0 4px;
    border-top: 1px solid var(--line);
  }

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

  .nav-link {
    padding: 12px 14px;
    min-height: 44px;
    display: flex;
    align-items: center;
    border-bottom: 0;
    border-left: 3px solid transparent;
  }

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

  .home-main,
  .inner-main,
  .error-main {
    padding-left: 18px;
    padding-right: 18px;
  }

  .fact-bar-text {
    padding: 10px 18px;
  }

  .footer-inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 24px;
    padding: 32px 18px 20px;
  }

  .footer-bottom {
    padding: 14px 18px 24px;
  }

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

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

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

  .cover-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
  }

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

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

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

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

  .ranking-item {
    grid-template-columns: 40px 72px minmax(0, 1fr);
    gap: 12px;
  }

  .ranking-position {
    font-size: 17px;
  }

  .update-row {
    grid-template-columns: minmax(0, 1fr) auto;
    grid-template-areas:
      "date topic"
      "name name"
      "range range";
    gap: 4px 10px;
  }

  .rank-row {
    grid-template-columns: 32px minmax(0, 1fr) auto;
    grid-template-areas:
      "index name topic"
      "index note note";
    gap: 4px 10px;
  }

  .update-item {
    grid-template-columns: minmax(0, 1fr) auto;
    grid-template-areas:
      "type topic"
      "name name"
      "range range"
      "note note";
    gap: 6px 10px;
  }

  .update-type {
    justify-self: start;
  }

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

  .topic-meta-key {
    margin-top: 8px;
  }

  .path-item {
    grid-template-columns: 32px minmax(0, 1fr);
    gap: 12px;
    padding: 16px;
  }

  .path-index {
    width: 28px;
    height: 28px;
    font-size: 14px;
  }

  .error-code {
    font-size: 44px;
  }

  .error-title {
    font-size: 22px;
  }
}

@media (max-width: 420px) {
  .cover-grid {
    grid-template-columns: minmax(0, 1fr);
  }

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

  .ranking-item {
    grid-template-columns: 34px minmax(0, 1fr);
    grid-template-areas:
      "position body"
      "cover body";
  }

  .ranking-position {
    grid-area: position;
  }

  .ranking-cover {
    grid-area: cover;
  }

  .ranking-body {
    grid-area: body;
  }

  .brand-slogan {
    display: none;
  }
}