:root {
  --color-bg: #f4efe6;
  --color-card: #ffffff;
  --color-ink: #2f3b32;
  --color-moss: #6b7f63;
  --color-clay: #c2703f;
  --color-line: #d9d1c2;
  --color-line-soft: #e7e0d2;
  --color-tint: #ece5d8;
  --font-head: "Source Han Sans SC", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SFMono-Regular", "JetBrains Mono", Consolas, "Liberation Mono", Menlo, monospace;
  --shell-width: 1120px;
  --radius-card: 6px;
  --radius-pill: 4px;
}

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

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

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

body {
  margin: 0;
  background-color: var(--color-bg);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

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

p {
  margin: 0;
}

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

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

a {
  color: var(--color-clay);
  text-decoration: none;
  transition: color 0.18s ease;
}

a:hover {
  color: #9d5730;
}

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

figure {
  margin: 0;
}

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

button {
  font: inherit;
  cursor: pointer;
}

time {
  font-family: var(--font-mono);
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-line);
}

.header-inner {
  display: flex;
  align-items: center;
  gap: 24px;
  max-width: var(--shell-width);
  margin: 0 auto;
  padding: 14px 24px;
}

.site-main {
  display: block;
}

.inner-main {
  max-width: var(--shell-width);
  margin: 0 auto;
  padding: 28px 24px 64px;
}

.section {
  max-width: var(--shell-width);
  margin: 0 auto;
  padding: 52px 24px 0;
}

.section-block {
  margin-top: 44px;
}

.section-head {
  margin-bottom: 22px;
}

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

.section-desc,
.section-lead,
.section-note,
.section-intro {
  margin-top: 8px;
  max-width: 760px;
  color: var(--color-moss);
  font-size: 15px;
}

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

.section-foot {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  margin-top: 20px;
}

/* ============ utility bar ============ */

.utility-bar {
  background-color: var(--color-ink);
  color: #e8e2d6;
  font-size: 13px;
}

.utility-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 20px;
  max-width: var(--shell-width);
  margin: 0 auto;
  padding: 7px 24px;
}

.utility-lang {
  font-weight: 600;
  color: #f4efe6;
}

.utility-status {
  color: #c3cbb9;
}

.utility-link {
  margin-left: auto;
  color: #f0c9a8;
}

.utility-link:hover {
  color: #ffffff;
}

/* ============ header / nav ============ */

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

.brand:hover {
  color: var(--color-clay);
}

.brand-mark {
  display: inline-block;
  width: 14px;
  height: 26px;
  background-color: var(--color-clay);
  border-radius: 3px 3px 3px 0;
  flex: none;
}

.brand-text {
  font-family: var(--font-head);
  font-size: 19px;
  font-weight: 700;
  line-height: 1.2;
}

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

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

.nav-list li {
  display: block;
}

.nav-list a {
  display: block;
  padding: 8px 13px;
  border-radius: var(--radius-pill);
  color: var(--color-ink);
  font-size: 15px;
}

.nav-list a:hover {
  background-color: var(--color-tint);
  color: var(--color-ink);
}

.nav-list a.is-current {
  background-color: var(--color-ink);
  color: #f4efe6;
}

.nav-toggle {
  display: none;
  margin-left: auto;
  width: 44px;
  height: 44px;
  padding: 11px 10px;
  background-color: transparent;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-pill);
}

.nav-toggle-bar {
  display: block;
  height: 2px;
  margin: 4px 0;
  background-color: var(--color-ink);
  border-radius: 2px;
}

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

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--color-moss);
}

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

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

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

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

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

.page-title {
  font-size: 32px;
  font-weight: 700;
}

.page-description,
.page-lead {
  margin-top: 12px;
  max-width: 760px;
  color: var(--color-moss);
  font-size: 16px;
}

.page-lead {
  color: var(--color-ink);
}

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

.btn {
  display: inline-block;
  padding: 11px 22px;
  border-radius: var(--radius-pill);
  font-size: 15px;
  font-weight: 600;
  line-height: 1.4;
}

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

.btn-primary:hover {
  background-color: #a85c31;
  color: #ffffff;
}

.btn-ghost {
  border: 1px solid var(--color-moss);
  color: var(--color-ink);
}

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

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--color-clay);
  font-size: 14px;
  font-weight: 600;
}

.link-arrow::after {
  content: "→";
  font-family: var(--font-mono);
}

.link-arrow:hover {
  color: #9d5730;
}

.tag-link {
  display: inline-block;
  padding: 5px 12px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-pill);
  background-color: var(--color-card);
  color: var(--color-ink);
  font-size: 14px;
}

.tag-link:hover {
  border-color: var(--color-clay);
  color: var(--color-clay);
}

.tag {
  display: inline-block;
  padding: 2px 9px;
  border-radius: var(--radius-pill);
  background-color: var(--color-tint);
  color: var(--color-ink);
  font-size: 13px;
}

.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
}

.field-table {
  min-width: 560px;
  font-size: 15px;
}

.field-table caption,
.table-caption,
.field-table-caption {
  padding: 12px 16px;
  color: var(--color-moss);
  font-size: 14px;
  text-align: left;
}

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

.field-table thead th {
  border-top: none;
  background-color: var(--color-tint);
  color: var(--color-ink);
  font-family: var(--font-head);
  font-size: 14px;
}

.field-table tbody th {
  width: 22%;
  font-family: var(--font-head);
  font-weight: 700;
}

.field-table tbody tr:hover {
  background-color: #faf6ee;
}

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

.hero {
  border-bottom: 1px solid var(--color-line);
}

.hero-inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 44px;
  align-items: start;
  max-width: var(--shell-width);
  margin: 0 auto;
  padding: 48px 24px 52px;
}

.hero-eyebrow {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--color-clay);
}

.hero-title {
  margin-top: 12px;
  font-size: 32px;
  font-weight: 700;
}

.hero-lead {
  margin-top: 16px;
  max-width: 520px;
  color: var(--color-moss);
  font-size: 16px;
}

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

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 26px;
}

.hero-visual {
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
  overflow: hidden;
}

.hero-visual img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

.hero-caption {
  padding: 12px 16px;
  border-top: 1px solid var(--color-line-soft);
  color: var(--color-moss);
  font-size: 14px;
}

/* ============ home topic rows ============ */

.topic-rows {
  display: grid;
  gap: 0;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
  overflow: hidden;
}

.topic-row {
  display: grid;
  grid-template-columns: 240px minmax(0, 1fr) 200px 130px;
  gap: 20px;
  align-items: center;
  padding: 18px 20px;
  border-top: 1px solid var(--color-line-soft);
}

.topic-row:first-child {
  border-top: none;
}

.topic-row:hover {
  background-color: #faf6ee;
}

.topic-cell {
  margin: 0;
  font-size: 15px;
}

.topic-name {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.topic-index {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--color-clay);
}

.topic-name h3 {
  font-size: 17px;
}

.topic-desc {
  color: var(--color-ink);
}

.topic-audience {
  color: var(--color-moss);
  font-size: 14px;
}

.topic-enter {
  text-align: right;
}

/* ============ home cover wall ============ */

.section-wall {
  padding-top: 52px;
}

.wall-group {
  margin-top: 30px;
}

.wall-group:first-of-type {
  margin-top: 0;
}

.wall-group-title {
  font-size: 17px;
  padding-left: 12px;
  border-left: 3px solid var(--color-clay);
}

.cover-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 20px;
  margin-top: 16px;
}

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

.cover-card:hover {
  transform: translateY(-3px);
  border-color: var(--color-moss);
}

.cover-figure img {
  width: 100%;
  aspect-ratio: 3 / 4;
  object-fit: cover;
}

.cover-body {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 14px 16px 18px;
}

.cover-name {
  font-size: 17px;
}

.cover-tags {
  color: var(--color-clay);
  font-size: 13px;
}

.cover-note {
  color: var(--color-moss);
  font-size: 14px;
}

/* ============ home update list ============ */

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

.update-row {
  display: grid;
  grid-template-columns: 120px minmax(0, 1fr) 150px 110px;
  gap: 16px;
  align-items: center;
  padding: 14px 20px;
  border-top: 1px solid var(--color-line-soft);
  font-size: 15px;
}

.update-row:first-child {
  border-top: none;
}

.update-row:hover {
  background-color: #faf6ee;
}

.update-date {
  color: var(--color-moss);
  font-size: 14px;
}

.update-name {
  color: var(--color-ink);
  font-weight: 600;
}

.update-topic {
  color: var(--color-moss);
  font-size: 14px;
}

.update-kind,
.update-type {
  justify-self: start;
  padding: 2px 10px;
  border-radius: var(--radius-pill);
  background-color: var(--color-tint);
  color: var(--color-ink);
  font-size: 13px;
}

/* ============ home charts ============ */

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

.chart-card {
  padding: 20px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
}

.chart-title {
  font-size: 17px;
}

.chart-basis {
  margin-top: 8px;
  color: var(--color-moss);
  font-size: 14px;
}

.chart-items {
  margin-top: 14px;
  counter-reset: chart-rank;
}

.chart-items li {
  position: relative;
  padding: 8px 0 8px 30px;
  border-top: 1px solid var(--color-line-soft);
  font-size: 15px;
}

.chart-items li:first-child {
  border-top: none;
}

.chart-items li::before {
  counter-increment: chart-rank;
  content: counter(chart-rank);
  position: absolute;
  left: 0;
  top: 9px;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background-color: var(--color-tint);
  color: var(--color-ink);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 20px;
  text-align: center;
}

/* ============ home boundary note ============ */

.boundary-note {
  margin-top: 24px;
  padding: 20px 22px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
}

.boundary-subtitle {
  font-size: 17px;
}

.boundary-note p {
  margin-top: 10px;
  max-width: 760px;
  color: var(--color-moss);
  font-size: 15px;
}

.boundary-links {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
}

/* ============ topics page ============ */

.channel-row {
  display: grid;
  grid-template-columns: 200px minmax(0, 1fr) 150px;
  gap: 24px;
  align-items: start;
  padding: 22px 0;
  border-top: 1px solid var(--color-line);
}

.topic-channels .channel-row:first-of-type {
  border-top: none;
}

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

.channel-cover img {
  width: 100%;
  aspect-ratio: 3 / 4;
  object-fit: cover;
}

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

.channel-meta {
  margin-top: 12px;
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: 8px 14px;
  font-size: 15px;
}

.channel-meta dt {
  color: var(--color-moss);
  font-family: var(--font-head);
  font-size: 14px;
}

.channel-meta dd {
  margin: 0;
  color: var(--color-ink);
}

.channel-entry {
  text-align: right;
}

.guide-list {
  display: grid;
  gap: 16px;
  counter-reset: guide-step;
}

.guide-step {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 16px;
  align-items: start;
  padding: 18px 20px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
}

.guide-index {
  font-family: var(--font-mono);
  font-size: 20px;
  color: var(--color-clay);
  line-height: 1.3;
}

.guide-name {
  font-size: 17px;
}

.guide-text {
  margin-top: 6px;
  color: var(--color-moss);
  font-size: 15px;
}

.related-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

.related-item {
  padding: 16px 18px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
  font-size: 15px;
}

.related-item a {
  font-weight: 600;
}

.related-desc,
.related-note {
  display: block;
  margin-top: 6px;
  color: var(--color-moss);
  font-size: 14px;
}

/* ============ updates page ============ */

.updates-section,
.scope-section,
.feedback-section,
.related-section,
.field-section,
.boundary-section {
  margin-top: 44px;
}

.updates-visual {
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
  overflow: hidden;
  margin-bottom: 24px;
}

.updates-visual img {
  width: 100%;
  aspect-ratio: 16 / 7;
  object-fit: cover;
}

.visual-caption {
  padding: 12px 16px;
  border-top: 1px solid var(--color-line-soft);
  color: var(--color-moss);
  font-size: 14px;
}

.update-timeline {
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
  overflow: hidden;
}

.scope-list {
  display: grid;
  gap: 16px;
}

.scope-item {
  padding: 18px 20px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
}

.scope-title {
  font-size: 17px;
}

.scope-text {
  margin-top: 8px;
  color: var(--color-moss);
  font-size: 15px;
}

.feedback-steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

.feedback-step {
  padding: 18px 20px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
}

.step-index {
  display: inline-block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--color-clay);
}

.feedback-step .step-title,
.feedback-step .step-name {
  font-size: 17px;
}

.feedback-step .step-text {
  margin-top: 8px;
  color: var(--color-moss);
  font-size: 15px;
}

/* ============ fields page ============ */

.field-media {
  margin-bottom: 24px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
  overflow: hidden;
}

.field-media img {
  width: 100%;
  aspect-ratio: 16 / 7;
  object-fit: cover;
}

.field-media figcaption {
  padding: 12px 16px;
  border-top: 1px solid var(--color-line-soft);
  color: var(--color-moss);
  font-size: 14px;
}

.boundary-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
}

.boundary-item {
  padding: 18px 20px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
}

.boundary-name {
  font-size: 17px;
}

.boundary-text {
  margin-top: 8px;
  color: var(--color-moss);
  font-size: 15px;
}

/* ============ reading page ============ */

.page-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  gap: 40px;
  align-items: start;
}

.content-main {
  min-width: 0;
}

.reading-visual {
  margin: 24px 0 0;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
  overflow: hidden;
}

.reading-visual img {
  width: 100%;
  aspect-ratio: 16 / 7;
  object-fit: cover;
}

.reading-visual figcaption {
  padding: 12px 16px;
  border-top: 1px solid var(--color-line-soft);
  color: var(--color-moss);
  font-size: 14px;
}

.section-steps,
.section-points,
.section-scope,
.section-faq {
  margin-top: 40px;
}

.step-list {
  display: grid;
  gap: 14px;
  counter-reset: browse-step;
}

.step-item {
  position: relative;
  padding: 16px 20px 16px 56px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
}

.step-item::before {
  counter-increment: browse-step;
  content: counter(browse-step);
  position: absolute;
  left: 18px;
  top: 17px;
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--color-clay);
}

.step-item h3 {
  font-size: 17px;
}

.step-item p {
  margin-top: 6px;
  color: var(--color-moss);
  font-size: 15px;
}

.point-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

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

.point-item h3 {
  font-size: 17px;
}

.point-item p {
  margin-top: 6px;
  color: var(--color-moss);
  font-size: 15px;
}

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

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

.scope-column h3 {
  font-size: 17px;
}

.scope-provide h3 {
  color: var(--color-ink);
}

.scope-exclude h3 {
  color: var(--color-clay);
}

.scope-column .scope-list {
  margin-top: 12px;
  gap: 8px;
}

.scope-column .scope-list li {
  position: relative;
  padding-left: 16px;
  color: var(--color-moss);
  font-size: 15px;
}

.scope-column .scope-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 11px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--color-moss);
}

.scope-exclude .scope-list li::before {
  background-color: var(--color-clay);
}

.faq-list {
  display: grid;
  gap: 12px;
}

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

.faq-item summary {
  position: relative;
  padding: 15px 44px 15px 18px;
  font-family: var(--font-head);
  font-size: 16px;
  font-weight: 700;
  cursor: pointer;
  list-style: none;
}

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

.faq-item summary::after {
  content: "+";
  position: absolute;
  right: 18px;
  top: 14px;
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--color-clay);
}

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

.faq-item p {
  padding: 0 18px 16px;
  color: var(--color-moss);
  font-size: 15px;
}

.content-aside {
  padding: 20px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
}

.aside-title {
  font-size: 17px;
}

.aside-intro {
  margin-top: 8px;
  color: var(--color-moss);
  font-size: 14px;
}

.aside-list {
  margin-top: 14px;
  display: grid;
  gap: 10px;
}

.aside-list li {
  padding-top: 10px;
  border-top: 1px solid var(--color-line-soft);
  font-size: 15px;
}

.aside-list li:first-child {
  padding-top: 0;
  border-top: none;
}

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

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

.error-panel {
  max-width: 620px;
  padding: 32px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  background-color: var(--color-card);
}

.error-code {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--color-clay);
}

.error-title {
  margin-top: 10px;
  font-size: 32px;
}

.error-text {
  margin-top: 12px;
  color: var(--color-moss);
  font-size: 16px;
}

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

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

.site-footer {
  margin-top: 64px;
  border-top: 1px solid var(--color-line);
  background-color: var(--color-tint);
}

.footer-inner {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) repeat(3, minmax(0, 1fr));
  gap: 32px;
  max-width: var(--shell-width);
  margin: 0 auto;
  padding: 44px 24px 32px;
}

.footer-name {
  font-family: var(--font-head);
  font-size: 18px;
  font-weight: 700;
}

.footer-desc {
  margin-top: 10px;
  max-width: 320px;
  color: var(--color-moss);
  font-size: 14px;
}

.footer-title {
  font-size: 15px;
  color: var(--color-ink);
}

.footer-list {
  margin-top: 12px;
  display: grid;
  gap: 8px;
}

.footer-list a {
  color: var(--color-moss);
  font-size: 14px;
}

.footer-list a:hover {
  color: var(--color-clay);
}

.footer-bottom {
  max-width: var(--shell-width);
  margin: 0 auto;
  padding: 18px 24px 28px;
  border-top: 1px solid var(--color-line);
}

.footer-boundary {
  color: var(--color-moss);
  font-size: 13px;
}

.footer-copy {
  margin-top: 8px;
  color: var(--color-moss);
  font-size: 13px;
}

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

@media (max-width: 900px) {
  .header-inner {
    flex-wrap: wrap;
    gap: 12px;
    padding: 12px 20px;
  }

  .nav-toggle {
    display: block;
  }

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

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

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

  .nav-list a {
    padding: 12px 14px;
    font-size: 16px;
  }

  .hero-inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
    padding: 36px 20px 40px;
  }

  .hero-visual {
    order: 2;
  }

  .topic-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 8px;
    align-items: start;
  }

  .topic-enter {
    text-align: left;
  }

  .update-row {
    grid-template-columns: 110px minmax(0, 1fr);
    gap: 6px 14px;
  }

  .update-topic,
  .update-kind,
  .update-type {
    grid-column: 2;
  }

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

  .channel-row {
    grid-template-columns: 160px minmax(0, 1fr);
    gap: 18px;
  }

  .channel-entry {
    grid-column: 2;
    text-align: left;
  }

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

  .content-aside {
    max-width: 520px;
  }

  .footer-inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 26px;
  }

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

@media (max-width: 600px) {
  body {
    font-size: 15px;
  }

  .utility-inner {
    padding: 7px 16px;
  }

  .utility-link {
    margin-left: 0;
  }

  .header-inner {
    padding: 10px 16px;
  }

  .brand-text {
    font-size: 17px;
  }

  .inner-main,
  .section {
    padding-left: 16px;
    padding-right: 16px;
  }

  .inner-main {
    padding-top: 20px;
    padding-bottom: 48px;
  }

  .section {
    padding-top: 40px;
  }

  .section-block {
    margin-top: 34px;
  }

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

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

  .hero-inner {
    padding: 28px 16px 34px;
  }

  .cover-grid {
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 14px;
  }

  .cover-body {
    padding: 12px 12px 14px;
  }

  .update-row {
    grid-template-columns: minmax(0, 1fr);
    padding: 14px 16px;
  }

  .update-topic,
  .update-kind,
  .update-type {
    grid-column: 1;
  }

  .topic-row,
  .chart-card,
  .boundary-note {
    padding: 16px;
  }

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

  .channel-cover {
    max-width: 200px;
  }

  .channel-entry {
    grid-column: 1;
  }

  .channel-meta {
    grid-template-columns: 84px minmax(0, 1fr);
  }

  .guide-step {
    grid-template-columns: 34px minmax(0, 1fr);
    padding: 16px;
  }

  .step-item {
    padding: 14px 16px 14px 48px;
  }

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

  .feedback-steps,
  .boundary-list,
  .point-list,
  .related-list {
    grid-template-columns: minmax(0, 1fr);
  }

  .error-main {
    padding: 48px 16px 64px;
  }

  .error-panel {
    padding: 24px;
  }

  .footer-inner {
    grid-template-columns: minmax(0, 1fr);
    padding: 32px 16px 24px;
  }

  .footer-bottom {
    padding: 16px 16px 24px;
  }
}