:root {
  --color-primary: #1f6f63;
  --color-primary-dark: #175a50;
  --color-accent: #e8b06a;
  --color-bg: #f6f8f7;
  --color-surface: #ffffff;
  --color-text: #232a29;
  --color-muted: #5c6b68;
  --color-line: #dfe5e3;
  --color-soft: #eef3f1;
  --radius-sm: 4px;
  --radius-md: 8px;
  --shadow-sm: 0 1px 2px rgba(31, 111, 99, 0.06);
  --shadow-md: 0 4px 14px rgba(31, 111, 99, 0.08);
  --container: 1080px;
  --gap-sm: 12px;
  --gap-md: 20px;
  --gap-lg: 32px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
}

/* ============ base ============ */
* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  color: var(--color-text);
  background-color: var(--color-bg);
  font-feature-settings: "tnum" 1;
}

h1, h2, h3, h4 {
  margin: 0 0 12px;
  font-weight: 600;
  line-height: 1.35;
  color: var(--color-text);
}

p {
  margin: 0 0 12px;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover,
a:focus-visible {
  color: var(--color-primary-dark);
}

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

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

figure {
  margin: 0;
}

dl, dt, dd {
  margin: 0;
}

time {
  font-variant-numeric: tabular-nums;
}

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

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

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

/* ============ layout ============ */
.site-body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  background-color: var(--color-bg);
}

.site-main {
  display: block;
  width: 100%;
  flex: 1 0 auto;
}

.inner-main {
  max-width: var(--container);
  margin: 0 auto;
  padding: 24px 20px 56px;
}

.home-main {
  max-width: var(--container);
  margin: 0 auto;
  padding: 24px 20px 56px;
}

.site-factbar {
  background-color: var(--color-primary);
  color: #eaf3f1;
  font-size: 13px;
  line-height: 1.6;
}

.site-factbar p {
  max-width: var(--container);
  margin: 0 auto;
  padding: 8px 20px;
}

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

.header-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  gap: var(--gap-md);
  flex-wrap: wrap;
}

.brand {
  display: flex;
  flex-direction: column;
  color: var(--color-text);
  gap: 2px;
  flex: 0 0 auto;
}

.brand-name {
  font-size: 22px;
  font-weight: 600;
  color: var(--color-primary);
  line-height: 1.2;
}

.brand-slogan {
  font-size: 12px;
  color: var(--color-muted);
  line-height: 1.2;
}

.site-nav {
  flex: 1 1 auto;
  display: flex;
  justify-content: flex-end;
}

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

.nav-list li {
  display: block;
}

.nav-list a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  font-size: 15px;
  color: var(--color-text);
  font-weight: 500;
}

.nav-list a:hover,
.nav-list a:focus-visible {
  background-color: var(--color-soft);
  color: var(--color-primary-dark);
}

.nav-list a.is-current {
  color: var(--color-primary);
  background-color: var(--color-soft);
  font-weight: 600;
  box-shadow: inset 0 -2px 0 var(--color-primary);
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 10px;
  margin-left: auto;
  background-color: transparent;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
}

.nav-toggle-bar {
  display: block;
  width: 100%;
  height: 2px;
  background-color: var(--color-primary);
  border-radius: 1px;
}

.topic-quickbar {
  background-color: var(--color-soft);
  border-top: 1px solid var(--color-line);
  display: flex;
  align-items: center;
  gap: var(--gap-sm);
  padding: 8px 20px;
  max-width: 100%;
  overflow-x: auto;
}

.topic-quickbar-label {
  flex: 0 0 auto;
  font-size: 12px;
  color: var(--color-muted);
  padding-right: 8px;
  border-right: 1px solid var(--color-line);
}

.topic-quickbar-list {
  display: flex;
  gap: 6px;
  flex-wrap: nowrap;
}

.topic-quickbar-list li {
  flex: 0 0 auto;
}

.topic-quickbar-list a {
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  padding: 4px 12px;
  border-radius: 999px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  font-size: 13px;
  color: var(--color-primary);
  white-space: nowrap;
}

.topic-quickbar-list a:hover,
.topic-quickbar-list a:focus-visible {
  border-color: var(--color-primary);
  background-color: #ffffff;
}

.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
  font-size: 13px;
  color: var(--color-muted);
  margin-bottom: 16px;
}

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

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

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

.breadcrumb-current {
  color: var(--color-text);
  font-weight: 500;
}

.page-header {
  margin-bottom: 32px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--color-line);
}

.page-title {
  font-size: 32px;
  font-weight: 600;
  color: var(--color-text);
  margin: 0 0 12px;
}

.page-description {
  font-size: 16px;
  color: var(--color-muted);
  max-width: 68ch;
  margin: 0;
}

.section-title {
  font-size: 22px;
  font-weight: 600;
  color: var(--color-text);
  margin: 0 0 10px;
}

.section-intro,
.section-lead {
  font-size: 15px;
  color: var(--color-muted);
  max-width: 68ch;
  margin: 0 0 20px;
}

.section-head {
  margin-bottom: 18px;
}

.section-head h2 {
  font-size: 20px;
  margin: 0 0 6px;
}

.section-head p {
  font-size: 14px;
  color: var(--color-muted);
  margin: 0;
}

.section-footnote {
  margin-top: 20px;
  font-size: 14px;
  color: var(--color-muted);
}

.section-footnote a {
  margin-right: 12px;
}

/* ============ components: figures & covers ============ */
.hero-figure,
.cover-figure,
.topic-sample-media,
.update-thumb,
.rank-cover,
.field-figure-media,
.help-figure {
  overflow: hidden;
  border-radius: var(--radius-md);
  background-color: var(--color-soft);
}

.hero-figure img,
.cover-figure img,
.topic-sample-media img,
.update-thumb img,
.rank-cover img,
.field-figure-media img,
.help-figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.hero-figure figcaption,
.cover-figure figcaption,
.field-figure-media figcaption,
.help-figure figcaption {
  font-size: 13px;
  color: var(--color-muted);
  padding: 8px 4px 0;
}

/* ============ components: hero workbench ============ */
.hero-workbench {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
  gap: var(--gap-lg);
  align-items: start;
  padding: 8px 0 40px;
  border-bottom: 1px solid var(--color-line);
}

.hero-text {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.hero-title {
  font-size: 34px;
  font-weight: 600;
  line-height: 1.3;
  margin: 0;
  color: var(--color-text);
}

.hero-summary {
  font-size: 16px;
  color: var(--color-muted);
  max-width: 60ch;
  margin: 0;
}

.hero-paths {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 4px;
}

.hero-path a {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 12px 16px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  background-color: var(--color-surface);
  color: var(--color-text);
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.hero-path a:hover,
.hero-path a:focus-visible {
  transform: translateY(-2px);
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
}

.hero-path-name {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-primary);
}

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

.hero-visual {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.hero-figure {
  aspect-ratio: 16 / 10;
}

.hero-covers {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

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

/* ============ components: topic overview (home) ============ */
.topic-overview {
  padding: 40px 0;
  border-bottom: 1px solid var(--color-line);
}

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

.topic-column {
  padding: 18px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.topic-name {
  font-size: 17px;
  font-weight: 600;
  color: var(--color-primary);
  margin: 0;
}

.topic-scope {
  font-size: 13px;
  color: var(--color-muted);
  margin: 0;
  min-height: 42px;
}

.topic-samples {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-top: auto;
  padding-top: 8px;
  border-top: 1px dashed var(--color-line);
}

.topic-samples li {
  font-size: 13px;
}

.topic-samples a {
  color: var(--color-text);
}

.topic-samples a:hover,
.topic-samples a:focus-visible {
  color: var(--color-primary);
}

/* ============ components: home split sections ============ */
.home-split {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
  gap: var(--gap-lg);
  padding: 40px 0;
  border-bottom: 1px solid var(--color-line);
  align-items: start;
}

.home-split-secondary {
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
}

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

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

.cover-card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 10px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.cover-card:hover,
.cover-card:focus-within {
  transform: translateY(-3px);
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
}

.cover-card img {
  width: 100%;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border-radius: var(--radius-sm);
  background-color: var(--color-soft);
}

.cover-name {
  font-size: 15px;
  font-weight: 600;
  margin: 0;
  color: var(--color-text);
}

.cover-meta {
  font-size: 12px;
  color: var(--color-muted);
  margin: 0;
}

.update-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.update-item {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px;
  padding: 12px 0;
  border-bottom: 1px dashed var(--color-line);
  font-size: 14px;
}

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

.update-item time {
  flex: 0 0 auto;
  color: var(--color-muted);
  font-size: 13px;
}

.update-topic {
  flex: 0 0 auto;
  padding: 1px 8px;
  background-color: var(--color-soft);
  color: var(--color-primary);
  border-radius: 999px;
  font-size: 12px;
}

.update-name {
  flex: 1 1 auto;
  color: var(--color-text);
  font-size: 14px;
  font-weight: 500;
  margin: 0;
}

.rank-list {
  display: flex;
  flex-direction: column;
}

.rank-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px dashed var(--color-line);
  font-size: 14px;
}

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

.rank-no {
  flex: 0 0 34px;
  height: 34px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  background-color: var(--color-soft);
  color: var(--color-primary);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.rank-name {
  flex: 1 1 auto;
  min-width: 0;
  margin: 0;
  font-size: 15px;
  font-weight: 500;
  color: var(--color-text);
}

.rank-change {
  flex: 0 0 auto;
  font-size: 12px;
  padding: 1px 8px;
  border-radius: 999px;
  background-color: var(--color-soft);
  color: var(--color-muted);
}

.rank-change.is-up {
  background-color: #e6f1ee;
  color: var(--color-primary);
}

.rank-change.is-down {
  background-color: #f4ece0;
  color: #8a5a1b;
}

.rank-change.is-flat {
  background-color: var(--color-soft);
  color: var(--color-muted);
}

.field-digest {
  display: grid;
  grid-template-columns: max-content minmax(0, 1fr);
  gap: 8px 16px;
  font-size: 14px;
}

.field-digest dt {
  font-weight: 600;
  color: var(--color-primary);
  white-space: nowrap;
}

.field-digest dd {
  margin: 0;
  color: var(--color-text);
}

.split-more {
  margin: 16px 0 0;
  font-size: 14px;
}

.split-more a {
  font-weight: 500;
}

/* ============ components: home steps & feedback ============ */
.home-steps {
  padding: 40px 0;
  border-bottom: 1px solid var(--color-line);
}

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

.step-item {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 20px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
}

.step-no,
.step-index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background-color: var(--color-primary);
  color: #ffffff;
  font-weight: 600;
  font-size: 14px;
  font-variant-numeric: tabular-nums;
}

.step-name {
  font-size: 16px;
  font-weight: 600;
  margin: 0;
  color: var(--color-text);
}

.step-text {
  font-size: 14px;
  color: var(--color-muted);
  margin: 0;
}

.feedback-block {
  margin-top: 28px;
  padding: 20px 24px;
  background-color: var(--color-soft);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--color-accent);
}

.feedback-title {
  font-size: 16px;
  font-weight: 600;
  margin: 0 0 8px;
  color: var(--color-text);
}

.feedback-block p {
  font-size: 14px;
  color: var(--color-muted);
  margin: 0 0 6px;
}

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

/* ============ components: site index ============ */
.site-index {
  padding: 40px 0 8px;
}

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

.index-column {
  padding: 18px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.index-column:hover,
.index-column:focus-within {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-sm);
}

.index-column h3 {
  font-size: 16px;
  margin: 0 0 8px;
}

.index-column h3 a {
  color: var(--color-text);
}

.index-column h3 a:hover,
.index-column h3 a:focus-visible {
  color: var(--color-primary);
}

.index-column p {
  font-size: 13px;
  color: var(--color-muted);
  margin: 0;
}

/* ============ components: footer ============ */
.site-footer {
  background-color: #1c2a28;
  color: #c8d3d0;
  margin-top: 40px;
}

.footer-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 40px 20px 24px;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--gap-lg);
}

.footer-group-title {
  font-size: 14px;
  font-weight: 600;
  color: #ffffff;
  margin: 0 0 12px;
}

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

.footer-group a {
  font-size: 13px;
  color: #c8d3d0;
}

.footer-group a:hover,
.footer-group a:focus-visible {
  color: #ffffff;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.12);
}

.footer-bottom p {
  max-width: var(--container);
  margin: 0 auto;
  padding: 16px 20px 0;
  font-size: 12px;
  color: #9aa8a5;
  line-height: 1.7;
}

.footer-copy {
  padding-bottom: 24px !important;
}

/* ============ pages: topics ============ */
.topic-overview-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--gap-md);
}

.topic-overview-item {
  padding: 18px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
}

.topic-overview-item .topic-name {
  font-size: 16px;
  margin-bottom: 6px;
}

.topic-overview-item .topic-scope {
  min-height: 0;
}

.topic-samples {
  display: flex;
  flex-direction: column;
  gap: var(--gap-md);
}

.topic-sample {
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  gap: var(--gap-lg);
  padding: 20px 0;
  border-bottom: 1px solid var(--color-line);
  align-items: start;
}

.topic-sample:last-child {
  border-bottom: none;
}

.topic-sample-media {
  aspect-ratio: 3 / 4;
}

.topic-sample-body {
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-width: 0;
}

.topic-sample-name {
  font-size: 18px;
  font-weight: 600;
  margin: 0;
  color: var(--color-text);
}

.topic-sample-desc {
  font-size: 14px;
  color: var(--color-text);
  margin: 0;
  max-width: 68ch;
}

.topic-sample-note {
  font-size: 13px;
  color: var(--color-muted);
  margin: 0;
}

.topic-guide {
  margin-top: 40px;
  padding-top: 32px;
  border-top: 1px solid var(--color-line);
}

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

.guide-step {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 20px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
}

.guide-step-no {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background-color: var(--color-primary);
  color: #ffffff;
  font-weight: 600;
  font-size: 14px;
}

.guide-step-title {
  font-size: 16px;
  font-weight: 600;
  margin: 0;
  color: var(--color-text);
}

.guide-step-desc {
  font-size: 14px;
  color: var(--color-muted);
  margin: 0;
}

.topic-guide-note {
  margin-top: 20px;
  font-size: 14px;
  color: var(--color-muted);
}

/* ============ pages: updates ============ */
.section {
  padding: 32px 0;
  border-bottom: 1px solid var(--color-line);
}

.section:last-of-type {
  border-bottom: none;
}

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

.batch-card {
  padding: 18px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.batch-name {
  font-size: 16px;
  font-weight: 600;
  margin: 0;
  color: var(--color-primary);
}

.batch-scope {
  font-size: 14px;
  color: var(--color-text);
  margin: 0;
}

.batch-note {
  font-size: 13px;
  color: var(--color-muted);
  margin: 0;
}

.section-timeline .update-item {
  display: grid;
  grid-template-columns: 100px 96px 88px minmax(0, 1fr);
  gap: 16px;
  align-items: center;
  padding: 16px 0;
  border-bottom: 1px solid var(--color-line);
}

.section-timeline .update-item:last-child {
  border-bottom: none;
}

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

.update-batch {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 2px 8px;
  border-radius: 999px;
  background-color: var(--color-soft);
  color: var(--color-primary);
  font-size: 12px;
  white-space: nowrap;
}

.update-thumb {
  width: 88px;
  aspect-ratio: 3 / 4;
}

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

.update-body .update-name {
  font-size: 16px;
  font-weight: 600;
  margin: 0 0 4px;
}

.update-meta {
  font-size: 13px;
  color: var(--color-muted);
  margin: 0;
}

.section-view-guide .step-list {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.section-view-guide .step-item {
  flex-direction: row;
  align-items: flex-start;
  gap: 12px;
}

.section-view-guide .step-item .step-name {
  margin-bottom: 4px;
}

.section-view-guide .step-item .step-text {
  margin: 0;
}

.section-view-guide .step-item > .step-index {
  flex: 0 0 32px;
}

/* ============ pages: ranking ============ */
.rank-basis {
  padding: 8px 0 32px;
  border-bottom: 1px solid var(--color-line);
}

.rank-basis h2 {
  font-size: 22px;
  margin: 0 0 10px;
}

.rank-basis > p {
  font-size: 15px;
  color: var(--color-muted);
  max-width: 68ch;
  margin: 0 0 20px;
}

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

.rank-basis-col {
  padding: 18px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
}

.rank-basis-col h3 {
  font-size: 16px;
  font-weight: 600;
  margin: 0 0 10px;
  color: var(--color-primary);
}

.rank-basis-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.rank-basis-list li {
  font-size: 14px;
  color: var(--color-text);
  padding-left: 16px;
  position: relative;
}

.rank-basis-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--color-accent);
}

.rank-basis-note {
  margin-top: 16px;
  font-size: 14px;
  color: var(--color-muted);
}

.rank-basis-note a {
  margin-right: 12px;
}

.rank-list-section {
  padding: 32px 0;
  border-bottom: 1px solid var(--color-line);
}

.rank-list-section h2 {
  font-size: 22px;
  margin: 0 0 10px;
}

.rank-list-lead {
  font-size: 15px;
  color: var(--color-muted);
  max-width: 68ch;
  margin: 0 0 20px;
}

.rank-list-section .rank-item {
  display: grid;
  grid-template-columns: 44px 80px minmax(0, 1fr) max-content;
  gap: 16px;
  align-items: center;
  padding: 16px 0;
  border-bottom: 1px solid var(--color-line);
}

.rank-list-section .rank-item:last-child {
  border-bottom: none;
}

.rank-list-section .rank-no {
  width: 44px;
  height: 44px;
  font-size: 16px;
}

.rank-cover {
  width: 80px;
  aspect-ratio: 3 / 4;
}

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

.rank-body .rank-name {
  font-size: 16px;
  font-weight: 600;
  margin: 0 0 4px;
}

.rank-topic {
  font-size: 13px;
  color: var(--color-muted);
  margin: 0;
}

.rank-change-note {
  padding: 32px 0;
}

.rank-change-note h2 {
  font-size: 22px;
  margin: 0 0 10px;
}

.rank-change-note > p {
  font-size: 15px;
  color: var(--color-muted);
  max-width: 68ch;
  margin: 0 0 20px;
}

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

.change-note-item {
  padding: 18px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
}

.change-note-item h3 {
  font-size: 15px;
  font-weight: 600;
  margin: 0 0 8px;
  color: var(--color-primary);
}

.change-note-item p {
  font-size: 14px;
  color: var(--color-muted);
  margin: 0;
}

.change-note-tip {
  margin-top: 20px;
  font-size: 14px;
  color: var(--color-muted);
}

.change-note-tip a {
  margin-right: 12px;
}

/* ============ pages: fields ============ */
.page-header.section {
  padding-bottom: 24px;
}

.field-figure {
  padding: 32px 0;
  border-bottom: 1px solid var(--color-line);
}

.field-figure-media {
  max-width: 720px;
  aspect-ratio: 16 / 9;
}

.field-table-section {
  padding: 32px 0;
  border-bottom: 1px solid var(--color-line);
}

.table-scroll {
  width: 100%;
  overflow-x: auto;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  background-color: var(--color-surface);
}

.field-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  min-width: 560px;
}

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

.field-table th,
.field-table td {
  padding: 12px 16px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--color-line);
}

.field-table thead th {
  background-color: var(--color-soft);
  color: var(--color-primary);
  font-weight: 600;
  font-size: 13px;
  white-space: nowrap;
}

.field-table tbody th {
  font-weight: 600;
  color: var(--color-text);
  white-space: nowrap;
  background-color: #fbfcfc;
}

.field-table tbody tr:last-child th,
.field-table tbody tr:last-child td {
  border-bottom: none;
}

.field-table tbody tr:hover th,
.field-table tbody tr:hover td {
  background-color: #f4f8f7;
}

.field-condition-section {
  padding: 32px 0;
  border-bottom: 1px solid var(--color-line);
}

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

.condition-item {
  padding: 18px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
}

.condition-name {
  font-size: 15px;
  font-weight: 600;
  margin: 0 0 8px;
  color: var(--color-primary);
}

.condition-desc {
  font-size: 14px;
  color: var(--color-muted);
  margin: 0;
}

.field-scope-section {
  padding: 32px 0;
  border-bottom: 1px solid var(--color-line);
}

.scope-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px 24px;
  margin-bottom: 24px;
}

.scope-item {
  position: relative;
  padding-left: 20px;
  font-size: 14px;
  color: var(--color-text);
}

.scope-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 8px;
  height: 8px;
  border-radius: 2px;
  background-color: var(--color-accent);
}

.scope-update {
  padding: 20px 24px;
  background-color: var(--color-soft);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--color-primary);
}

.scope-update-title {
  font-size: 16px;
  font-weight: 600;
  margin: 0 0 8px;
  color: var(--color-text);
}

.scope-update p {
  font-size: 14px;
  color: var(--color-muted);
  margin: 0 0 8px;
}

.scope-update p:last-child {
  margin-bottom: 0;
}

.field-related-section {
  padding: 32px 0 8px;
}

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

.related-item {
  padding: 18px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.related-item:hover,
.related-item:focus-within {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-sm);
}

.related-name {
  font-size: 16px;
  font-weight: 600;
  margin: 0 0 8px;
}

.related-name a {
  color: var(--color-text);
}

.related-name a:hover,
.related-name a:focus-visible {
  color: var(--color-primary);
}

.related-desc {
  font-size: 13px;
  color: var(--color-muted);
  margin: 0;
}

/* ============ pages: help ============ */
.help-steps {
  padding: 8px 0 32px;
  border-bottom: 1px solid var(--color-line);
}

.steps-list {
  display: flex;
  flex-direction: column;
  gap: var(--gap-md);
}

.steps-list .step-item {
  flex-direction: row;
  align-items: flex-start;
  gap: 16px;
  padding: 20px;
}

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

.step-title {
  font-size: 16px;
  font-weight: 600;
  margin: 0 0 6px;
  color: var(--color-text);
}

.step-body p {
  font-size: 14px;
  color: var(--color-muted);
  margin: 0;
  max-width: 68ch;
}

.help-figure {
  margin-top: 24px;
  max-width: 720px;
  aspect-ratio: 16 / 9;
}

.help-feedback {
  padding: 32px 0;
  border-bottom: 1px solid var(--color-line);
}

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

.feedback-card {
  padding: 18px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
}

.feedback-card-title {
  font-size: 16px;
  font-weight: 600;
  margin: 0 0 10px;
  color: var(--color-primary);
}

.feedback-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.feedback-list li {
  position: relative;
  padding-left: 16px;
  font-size: 13px;
  color: var(--color-muted);
}

.feedback-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--color-accent);
}

.feedback-note {
  margin-top: 20px;
  font-size: 14px;
  color: var(--color-muted);
}

.help-faq {
  padding: 32px 0;
  border-bottom: 1px solid var(--color-line);
}

.faq-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.faq-item {
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color 0.2s ease;
}

.faq-item[open] {
  border-color: var(--color-primary);
}

.faq-question {
  list-style: none;
  cursor: pointer;
  padding: 16px 44px 16px 20px;
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text);
  position: relative;
  min-height: 44px;
  display: flex;
  align-items: center;
}

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

.faq-question::after {
  content: "+";
  position: absolute;
  right: 18px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 20px;
  color: var(--color-primary);
  line-height: 1;
  transition: transform 0.2s ease;
}

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

.faq-question:hover,
.faq-question:focus-visible {
  color: var(--color-primary);
}

.faq-answer {
  padding: 0 20px 18px;
}

.faq-answer p {
  font-size: 14px;
  color: var(--color-muted);
  margin: 0;
  max-width: 68ch;
}

.help-next {
  padding: 32px 0 8px;
}

.next-links {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--gap-md);
}

.next-link-item a {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 16px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  color: var(--color-text);
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.next-link-item a:hover,
.next-link-item a:focus-visible {
  transform: translateY(-2px);
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
}

.next-link-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-primary);
}

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

/* ============ pages: 404 ============ */
.error-main {
  max-width: var(--container);
  margin: 0 auto;
  padding: 48px 20px 56px;
}

.error-panel {
  text-align: center;
  padding: 40px 20px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
}

.error-code {
  font-size: 64px;
  font-weight: 600;
  color: var(--color-primary);
  margin: 0 0 8px;
  font-variant-numeric: tabular-nums;
  line-height: 1;
}

.error-title {
  font-size: 24px;
  margin: 0 0 12px;
}

.error-desc {
  font-size: 15px;
  color: var(--color-muted);
  max-width: 60ch;
  margin: 0 auto 24px;
}

.error-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
  margin: 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 22px;
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-weight: 500;
  border: 1px solid transparent;
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

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

.btn-primary:hover,
.btn-primary:focus-visible {
  background-color: var(--color-primary-dark);
  color: #ffffff;
}

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

.btn-ghost:hover,
.btn-ghost:focus-visible {
  background-color: var(--color-soft);
  color: var(--color-primary-dark);
}

.error-links {
  margin-top: 32px;
}

.error-link-list {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--gap-md);
}

.error-link-list a {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 12px 16px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  font-size: 14px;
  color: var(--color-text);
}

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

/* ============ responsive ============ */
@media (max-width: 1024px) {
  .hero-workbench {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--gap-md);
  }

  .hero-title {
    font-size: 28px;
  }

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

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

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

  .index-columns,
  .batch-grid,
  .rank-basis-grid,
  .change-note-grid,
  .related-list,
  .feedback-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

  .next-links,
  .error-link-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .topic-sample {
    grid-template-columns: 180px minmax(0, 1fr);
    gap: var(--gap-md);
  }

  .section-timeline .update-item {
    grid-template-columns: 90px 84px 72px minmax(0, 1fr);
    gap: 12px;
  }

  .update-thumb {
    width: 72px;
  }
}

@media (max-width: 768px) {
  .header-inner {
    padding: 12px 16px;
    gap: 12px;
  }

  .site-nav {
    flex: 1 0 100%;
    order: 3;
    justify-content: flex-start;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-list {
    display: none;
    flex-direction: column;
    width: 100%;
    gap: 2px;
    padding-top: 6px;
    border-top: 1px solid var(--color-line);
    margin-top: 6px;
  }

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

  .nav-list a {
    width: 100%;
    min-height: 44px;
    padding: 10px 12px;
  }

  .topic-quickbar {
    padding: 8px 16px;
  }

  .home-main,
  .inner-main,
  .error-main {
    padding: 20px 16px 40px;
  }

  .hero-workbench {
    padding-bottom: 28px;
  }

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

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

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

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

  .index-columns,
  .batch-grid,
  .rank-basis-grid,
  .change-note-grid,
  .related-list,
  .feedback-grid,
  .condition-list,
  .scope-list {
    grid-template-columns: minmax(0, 1fr);
  }

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

  .topic-sample-media {
    max-width: 220px;
  }

  .section-timeline .update-item {
    grid-template-columns: 72px minmax(0, 1fr);
    grid-template-areas:
      "thumb body"
      "date body"
      "batch body";
    gap: 6px 14px;
    align-items: start;
  }

  .section-timeline .update-thumb {
    grid-area: thumb;
    width: 72px;
  }

  .section-timeline .update-date {
    grid-area: date;
  }

  .section-timeline .update-batch {
    grid-area: batch;
    justify-self: start;
  }

  .section-timeline .update-body {
    grid-area: body;
  }

  .rank-list-section .rank-item {
    grid-template-columns: 40px 64px minmax(0, 1fr);
    grid-template-areas:
      "no cover body"
      "no cover change";
    gap: 6px 14px;
    align-items: start;
  }

  .rank-list-section .rank-no {
    grid-area: no;
    width: 40px;
    height: 40px;
  }

  .rank-cover {
    grid-area: cover;
    width: 64px;
  }

  .rank-list-section .rank-body {
    grid-area: body;
  }

  .rank-list-section .rank-change {
    grid-area: change;
    justify-self: start;
  }

  .footer-inner {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--gap-md);
    padding: 32px 16px 20px;
  }

  .footer-bottom p {
    padding-left: 16px;
    padding-right: 16px;
  }

  .next-links,
  .error-link-list {
    grid-template-columns: minmax(0, 1fr);
  }

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

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

@media (max-width: 480px) {
  .brand-name {
    font-size: 19px;
  }

  .brand-slogan {
    font-size: 11px;
  }

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

  .hero-covers {
    gap: 10px;
  }

  .cover-grid {
    gap: 12px;
  }

  .cover-card {
    padding: 8px;
  }

  .cover-name {
    font-size: 14px;
  }

  .update-item {
    font-size: 13px;
  }

  .rank-no {
    flex-basis: 30px;
    height: 30px;
    font-size: 13px;
  }

  .error-code {
    font-size: 52px;
  }

  .field-digest {
    grid-template-columns: minmax(0, 1fr);
    gap: 2px 0;
  }

  .field-digest dt {
    margin-top: 8px;
  }

  .feedback-block,
  .scope-update {
    padding: 16px;
  }
}

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

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