:root {
  --color-surface: #fafafa;
  --color-surface-alt: #f0f0f0;
  --color-surface-deep: #e1e2e2;
  --color-ink: #2d3430;
  --color-ink-soft: #56615b;
  --color-ink-muted: #727e77;
  --color-line: #d5d6d6;
  --color-primary: #0a8442;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #d8e9e0;
  --color-accent: #0c8844;
  --color-accent-ink: #ffffff;
  --color-highlight: #cfe5d9;
  --color-focus: #04813d;
  --color-contrast-surface: #0e2017;
  --color-contrast-ink: #e4e7e5;
  --color-contrast-line: #3d4c44;
  --color-contrast-accent: #14eb76;
  --overlay-scrim: linear-gradient(180deg, rgba(14, 32, 23, 0.35) 0%, rgba(14, 32, 23, 0.72) 55%, rgba(14, 32, 23, 0.92) 100%);
  --font-heading: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-body: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --text-xs: 12.3px;
  --text-sm: 16.5px;
  --text-base: 19px;
  --text-lg: 25.3px;
  --text-xl: 33.8px;
  --text-2xl: 45.0px;
  --text-3xl: 60.0px;
  --text-4xl: 80.0px;
  --text-display: clamp(35px, 7.2vw, 92px);
  --text-figure: clamp(29px, 5.2vw, 66px);
  --weight-heading: 742;
  --weight-body: 400;
  --leading-body: 1.93;
  --leading-heading: 1.3;
  --tracking-heading: -0.009em;
  --radius-sm: 1px;
  --radius-md: 4px;
  --radius-lg: 6px;
  --radius-pill: 6px;
  --border-thin: 2px;
  --border-thick: 3px;
  --shadow-1: none;
  --shadow-2: none;
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1100px;
  --measure: 63ch;
  --gutter: 24px;
  --section-y: 80px;
  --section-y-lg: 112px;
}

/* ============================================================
   1. 基础重置与中文排版
   ============================================================ */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 96px;
}

body {
  margin: 0;
  background: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  font-variant-numeric: tabular-nums;
  -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3,
h4,
h5,
h6,
p,
figure,
blockquote,
dl,
dd,
ol,
ul {
  margin: 0;
}

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

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

button,
input,
select,
textarea {
  font: inherit;
  color: inherit;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
  text-wrap: balance;
}

h1 {
  font-size: var(--text-3xl);
}

h2 {
  font-size: var(--text-2xl);
}

h3 {
  font-size: var(--text-xl);
}

h4 {
  font-size: var(--text-lg);
}

p,
li {
  max-width: var(--measure);
}

a {
  color: var(--color-primary);
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

a:hover {
  color: var(--color-ink);
}

:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 1px;
}

.section--deep :focus-visible,
.site-footer :focus-visible {
  outline-color: var(--color-contrast-accent);
}

/* ============================================================
   2. 布局容器与工具类
   ============================================================ */

.shell {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  padding-block: var(--section-y);
}

.section--lg {
  padding-block: var(--section-y-lg);
}

.section--alt {
  background: var(--color-surface-alt);
}

.section--deep {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.section--deep h1,
.section--deep h2,
.section--deep h3,
.section--deep h4,
.section--deep .section-title {
  color: var(--color-contrast-ink);
}

.section--deep a {
  color: var(--color-contrast-accent);
}

.grid {
  display: grid;
  gap: var(--gutter);
}

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

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

.measure {
  max-width: var(--measure);
}

.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

.muted {
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.section--deep .muted {
  color: var(--color-contrast-ink);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

/* ============================================================
   3. 分隔语言：点线与短刻度
   ============================================================ */

.rule-dot {
  height: 0;
  margin-block: var(--space-4);
  border: 0;
  border-top: var(--border-thin) dotted var(--color-line);
}

.rule-dot--tight {
  margin-block: var(--space-3);
}

.section--deep .rule-dot,
.site-footer .rule-dot {
  border-top-color: var(--color-contrast-line);
}

/* ============================================================
   4. 标题体系与正文
   ============================================================ */

.section-head {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  margin-bottom: var(--space-4);
  padding-left: var(--space-2);
  border-left: var(--border-thick) solid var(--color-primary);
}

.section--deep .section-head {
  border-left-color: var(--color-contrast-accent);
}

.section-head--plain {
  border-left: 0;
  padding-left: 0;
}

.section-kicker {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--color-ink-muted);
}

.section--deep .section-kicker {
  color: var(--color-contrast-accent);
}

.section-index {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-2xl);
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--color-primary);
  font-variant-numeric: tabular-nums;
}

.section--deep .section-index {
  color: var(--color-contrast-accent);
}

.display-title {
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: 1.02;
  letter-spacing: -0.02em;
  color: var(--color-ink);
  max-width: 18ch;
}

.jersey {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 800;
  line-height: 0.9;
  letter-spacing: -0.04em;
  color: var(--color-primary);
  font-variant-numeric: tabular-nums;
}

.section--deep .jersey {
  color: var(--color-contrast-accent);
}

.lede {
  font-size: var(--text-lg);
  line-height: 1.55;
  color: var(--color-ink-soft);
  max-width: var(--measure);
}

.section--deep .lede {
  color: var(--color-contrast-ink);
}

.prose {
  max-width: var(--measure);
}

.prose > * + * {
  margin-top: var(--space-2);
}

.prose h2,
.prose h3 {
  margin-top: var(--space-4);
}

.prose ul,
.prose ol {
  list-style: none;
  padding-left: 0;
}

.prose li {
  position: relative;
  padding-left: var(--space-3);
}

.prose li + li {
  margin-top: var(--space-1);
}

.prose li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 10px;
  height: 2px;
  background: var(--color-primary);
}

.section--deep .prose li::before {
  background: var(--color-contrast-accent);
}

.quote {
  margin-block: var(--space-4);
  padding: var(--space-3);
  border-left: var(--border-thick) solid var(--color-primary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  background: var(--color-highlight);
  color: var(--color-ink);
  font-size: var(--text-lg);
  line-height: 1.5;
  max-width: var(--measure);
}

.quote p {
  max-width: 100%;
}

.quote p + p {
  margin-top: var(--space-2);
}

.section--deep .quote {
  background: transparent;
  border-left-color: var(--color-contrast-accent);
  color: var(--color-contrast-ink);
}

/* ============================================================
   5. 按钮 / 链接 / 标签 / 筛选
   ============================================================ */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  min-height: 48px;
  padding: 10px var(--space-3);
  font-family: inherit;
  font-size: var(--text-base);
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
  color: var(--color-ink);
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-ink);
  border-radius: var(--radius-sm);
  cursor: pointer;
}

.btn:hover {
  color: var(--color-primary);
  background: var(--color-surface-alt);
  border-color: var(--color-primary);
}

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

.btn--primary:hover {
  color: var(--color-primary-ink);
  background: color-mix(in srgb, var(--color-primary) 82%, #000000);
  border-color: color-mix(in srgb, var(--color-primary) 82%, #000000);
}

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

.section--deep .btn {
  color: var(--color-contrast-ink);
  background: transparent;
  border-color: var(--color-contrast-ink);
}

.section--deep .btn:hover {
  color: var(--color-contrast-surface);
  background: var(--color-contrast-ink);
  border-color: var(--color-contrast-ink);
}

.section--deep .btn--primary {
  color: var(--color-contrast-surface);
  background: var(--color-contrast-accent);
  border-color: var(--color-contrast-accent);
}

.section--deep .btn--primary:hover {
  color: var(--color-contrast-surface);
  background: color-mix(in srgb, var(--color-contrast-accent) 80%, #ffffff);
  border-color: color-mix(in srgb, var(--color-contrast-accent) 80%, #ffffff);
}

.link-more {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-primary);
  text-decoration: none;
}

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

.link-more:hover {
  color: var(--color-ink);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

.section--deep .link-more {
  color: var(--color-contrast-accent);
}

.section--deep .link-more:hover {
  color: var(--color-contrast-ink);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 8px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 600;
  line-height: 1.4;
  color: var(--color-ink-muted);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
}

.section--deep .tag {
  color: var(--color-contrast-ink);
  border-color: var(--color-contrast-line);
}

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin-bottom: var(--space-3);
}

.chip {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 8px 14px;
  font-family: inherit;
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1.2;
  color: var(--color-ink-soft);
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  cursor: pointer;
}

.chip:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.chip[aria-pressed="true"],
.chip.is-active {
  color: var(--color-primary-ink);
  background: var(--color-primary);
  border-color: var(--color-primary);
}

/* ============================================================
   6. 卡片 / 数据单元
   ============================================================ */

.card {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding: var(--space-3);
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  transition: border-color 140ms ease;
}

.card:hover,
.card:focus-within {
  border-color: var(--color-primary);
}

.card__title {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: 1.3;
  color: var(--color-ink);
}

.card__meta {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.section--deep .card {
  background: transparent;
  border-color: var(--color-contrast-line);
}

.section--deep .card:hover,
.section--deep .card:focus-within {
  border-color: var(--color-contrast-accent);
}

.section--deep .card__title {
  color: var(--color-contrast-ink);
}

.section--deep .card__meta {
  color: var(--color-contrast-ink);
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: var(--space-3);
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
}

.stat__value {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-2xl);
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--color-primary);
  font-variant-numeric: tabular-nums;
}

.stat__label {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-ink);
}

.stat__meta {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.section--deep .stat {
  background: transparent;
  border-color: var(--color-contrast-line);
}

.section--deep .stat__value {
  color: var(--color-contrast-accent);
}

.section--deep .stat__label,
.section--deep .stat__meta {
  color: var(--color-contrast-ink);
}

/* ============================================================
   7. 技能树式步骤
   ============================================================ */

.tree {
  list-style: none;
  margin: 0;
  padding: 0;
}

.tree__item {
  position: relative;
  margin-left: 9px;
  padding-left: var(--space-6);
  padding-bottom: var(--space-4);
  border-left: var(--border-thin) solid var(--color-line);
}

.tree__item:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.tree__item::before {
  content: "";
  position: absolute;
  left: -9px;
  top: 6px;
  width: 16px;
  height: 16px;
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-primary);
  border-radius: var(--radius-sm);
}

.section--deep .tree__item {
  border-left-color: var(--color-contrast-line);
}

.section--deep .tree__item::before {
  background: var(--color-contrast-surface);
  border-color: var(--color-contrast-accent);
}

.tree__title {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: 1.3;
  color: var(--color-ink);
}

.section--deep .tree__title {
  color: var(--color-contrast-ink);
}

.tree__body {
  margin-top: var(--space-1);
  font-size: var(--text-base);
  color: var(--color-ink-soft);
  max-width: var(--measure);
}

.section--deep .tree__body {
  color: var(--color-contrast-ink);
}

/* ============================================================
   8. 折叠分区
   ============================================================ */

.fold {
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
}

.fold + .fold {
  margin-top: calc(var(--border-thin) * -1);
}

.fold__summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  min-height: 56px;
  padding: var(--space-2) var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: 600;
  line-height: 1.3;
  color: var(--color-ink);
  cursor: pointer;
  list-style: none;
}

.fold__summary::-webkit-details-marker {
  display: none;
}

.fold__summary::after {
  content: "+";
  flex: none;
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  font-weight: 800;
  color: var(--color-primary);
}

.fold[open] .fold__summary::after {
  content: "–";
}

.fold[open] .fold__summary {
  border-bottom: var(--border-thin) dashed var(--color-line);
}

.fold__body {
  padding: var(--space-3);
  font-size: var(--text-base);
  color: var(--color-ink-soft);
}

.fold__body p {
  max-width: var(--measure);
}

/* ============================================================
   9. 图片容器（图录式）
   ============================================================ */

.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  background: var(--color-surface-deep);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
}

.media-frame img,
.media-frame picture,
.media-frame picture img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

.media-frame--portrait {
  aspect-ratio: 3 / 4;
}

.media-frame--square {
  aspect-ratio: 1 / 1;
}

.media-frame--wide {
  aspect-ratio: 21 / 9;
}

.media-frame__scrim {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  gap: var(--space-1);
  padding: var(--space-3);
  background: var(--overlay-scrim);
  color: var(--color-contrast-ink);
}

.media-frame__scrim > * {
  max-width: 34ch;
}

.media-frame__caption {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.6;
  color: var(--color-contrast-ink);
}

.media-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-2);
}

.media-grid .media-frame {
  aspect-ratio: 1 / 1;
}

/* ============================================================
   10. 面包屑与页内索引条
   ============================================================ */

.breadcrumb {
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 4px var(--space-2);
  list-style: none;
  margin: 0;
  padding: 0;
}

.breadcrumb li {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  max-width: none;
}

.breadcrumb li + li::before {
  content: "⁄";
  font-family: var(--font-mono);
  color: var(--color-line);
}

.breadcrumb a {
  color: var(--color-ink-soft);
  text-decoration: none;
}

.breadcrumb a:hover {
  color: var(--color-primary);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

.index-bar {
  position: sticky;
  top: 66px;
  z-index: 30;
  display: flex;
  gap: var(--space-1);
  overflow-x: auto;
  padding: var(--space-1) 0;
  background: var(--color-surface);
  border-bottom: var(--border-thin) dashed var(--color-line);
}

.index-bar__link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 44px;
  padding: 6px 12px;
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1.2;
  white-space: nowrap;
  text-decoration: none;
  color: var(--color-ink-soft);
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-sm);
}

.index-bar__link:hover {
  color: var(--color-ink);
  border-color: var(--color-line);
  background: var(--color-surface-alt);
}

.index-bar__link.is-current {
  color: var(--color-primary);
  background: var(--color-primary-soft);
  border-color: var(--color-primary);
  border-left-width: var(--border-thick);
}

/* ============================================================
   11. 跳转链接
   ============================================================ */

.skip-link {
  position: fixed;
  top: var(--space-2);
  left: var(--space-2);
  z-index: 200;
  display: inline-flex;
  align-items: center;
  min-height: 48px;
  padding: 10px var(--space-3);
  font-size: var(--text-base);
  font-weight: 600;
  text-decoration: none;
  color: var(--color-contrast-ink);
  background: var(--color-contrast-surface);
  border: var(--border-thin) solid var(--color-contrast-surface);
  border-radius: var(--radius-sm);
  transform: translateY(calc(-100% - var(--space-6)));
  transition: transform 160ms ease;
}

.skip-link:focus {
  transform: translateY(0);
  outline: 2px solid var(--color-focus);
  outline-offset: 1px;
}

/* ============================================================
   12. 页头
   ============================================================ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: var(--color-surface);
  border-bottom: var(--border-thin) solid var(--color-ink);
}

.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 3px;
  background: var(--color-surface-deep);
  pointer-events: none;
}

.scroll-progress__bar {
  display: block;
  width: 0;
  height: 100%;
  background: var(--color-primary);
}

@media (prefers-reduced-motion: no-preference) {
  .scroll-progress__bar {
    transition: width 120ms linear;
  }
}

.site-header__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1) var(--space-3);
  min-height: 68px;
  padding-block: var(--space-1);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  color: var(--color-ink);
  border-radius: var(--radius-sm);
}

.brand__mark {
  display: grid;
  place-items: center;
  flex: none;
  width: 46px;
  height: 46px;
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.04em;
  color: var(--color-primary-ink);
  background: var(--color-primary);
  border-radius: var(--radius-sm);
}

.brand__text {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.brand__name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: 1.1;
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

.brand__sub {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.2;
  color: var(--color-ink-muted);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  min-height: 48px;
  margin-left: auto;
  padding: 8px 14px;
  font-family: inherit;
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1.2;
  color: var(--color-ink);
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-ink);
  border-radius: var(--radius-sm);
  cursor: pointer;
}

.nav-toggle:hover {
  color: var(--color-primary);
  background: var(--color-surface-alt);
  border-color: var(--color-primary);
}

.nav-toggle__bars {
  position: relative;
  display: block;
  flex: none;
  width: 20px;
  height: 2px;
  background: currentColor;
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 20px;
  height: 2px;
  background: currentColor;
}

.nav-toggle__bars::before {
  top: -6px;
}

.nav-toggle__bars::after {
  top: 6px;
}

.site-header[data-open] .nav-toggle__bars {
  background: transparent;
}

.site-header[data-open] .nav-toggle__bars::before {
  transform: translateY(6px) rotate(45deg);
}

.site-header[data-open] .nav-toggle__bars::after {
  transform: translateY(-6px) rotate(-45deg);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-left: auto;
  min-width: 0;
}

.site-nav__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 2px;
}

.site-nav__link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 44px;
  padding: 6px 10px;
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1.2;
  white-space: nowrap;
  text-decoration: none;
  color: var(--color-ink-soft);
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-sm);
  transition: background-color 140ms ease, border-color 140ms ease, color 140ms ease;
}

.site-nav__index {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-ink-muted);
  font-variant-numeric: tabular-nums;
}

.site-nav__link:hover {
  color: var(--color-ink);
  background: var(--color-surface-alt);
  border-color: var(--color-line);
}

.site-nav__link:hover .site-nav__index {
  color: var(--color-primary);
}

.site-nav__link[aria-current="page"] {
  color: var(--color-primary-ink);
  background: var(--color-primary);
  border-color: var(--color-primary);
}

.site-nav__link[aria-current="page"] .site-nav__index {
  color: var(--color-primary-ink);
}

.site-nav__link[aria-current="page"]::after {
  content: "✓";
  font-size: var(--text-xs);
  line-height: 1;
}

.site-nav__utility {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding-left: var(--space-2);
  border-left: var(--border-thin) dashed var(--color-line);
}

.util-link {
  font-size: var(--text-sm);
  font-weight: 600;
  white-space: nowrap;
  text-decoration: none;
  color: var(--color-primary);
  border-bottom: var(--border-thin) solid var(--color-primary);
  padding-bottom: 2px;
}

.util-link:hover {
  color: var(--color-ink);
  border-bottom-color: var(--color-ink);
}

.util-status {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 9px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 600;
  white-space: nowrap;
  color: var(--color-ink-soft);
  background: var(--color-surface-alt);
  border: var(--border-thin) dashed var(--color-line);
  border-radius: var(--radius-sm);
}

.util-status__dot {
  flex: none;
  width: 8px;
  height: 8px;
  background: var(--color-primary);
  border-radius: var(--radius-sm);
}

/* ============================================================
   13. 页脚
   ============================================================ */

.site-footer {
  margin-top: var(--space-8);
  padding-top: var(--section-y);
  padding-bottom: var(--space-4);
  color: var(--color-contrast-ink);
  background: var(--color-contrast-surface);
  border-top: var(--border-thick) solid var(--color-contrast-accent);
}

.site-footer__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  max-width: none;
  margin-bottom: var(--space-3);
  padding: 5px 10px;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-contrast-accent);
  border: var(--border-thin) dashed var(--color-contrast-line);
  border-radius: var(--radius-sm);
}

.site-footer__brand {
  max-width: 24ch;
  margin-bottom: var(--space-6);
  font-family: var(--font-heading);
  font-size: var(--text-3xl);
  font-weight: var(--weight-heading);
  line-height: 1.15;
  letter-spacing: var(--tracking-heading);
  color: var(--color-contrast-ink);
  text-wrap: balance;
}

.site-footer__accent {
  color: var(--color-contrast-accent);
}

.site-footer__nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2) var(--space-4);
}

.site-footer__nav a {
  padding-bottom: 2px;
  font-size: var(--text-base);
  font-weight: 600;
  text-decoration: none;
  color: var(--color-contrast-ink);
  border-bottom: var(--border-thin) solid transparent;
}

.site-footer__nav a:hover {
  color: var(--color-contrast-accent);
  border-bottom-color: var(--color-contrast-accent);
}

.site-footer__meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1) var(--space-3);
  max-width: none;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-contrast-ink);
}

.site-footer__note {
  max-width: var(--measure);
  margin-top: var(--space-2);
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-contrast-ink);
}

/* ============================================================
   14. 动效与显现
   ============================================================ */

html.has-js [data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 200ms ease-out, transform 200ms ease-out;
}

html.has-js [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

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

  html.has-js [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ============================================================
   15. 响应式
   ============================================================ */

@media (max-width: 1200px) {
  .brand__sub {
    display: none;
  }
}

@media (max-width: 1100px) {
  .util-status {
    display: none;
  }
}

@media (max-width: 1023px) {
  .nav-toggle {
    display: inline-flex;
  }

  .site-nav {
    display: none;
    flex-basis: 100%;
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-2);
    margin-left: 0;
    padding-top: var(--space-2);
    border-top: var(--border-thin) dashed var(--color-line);
  }

  .site-header[data-open] .site-nav {
    display: flex;
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
  }

  .site-nav__link {
    justify-content: flex-start;
    padding: 10px 12px;
    font-size: var(--text-base);
    border-color: var(--color-line);
  }

  .site-nav__utility {
    flex-wrap: wrap;
    padding-left: 0;
    padding-top: var(--space-2);
    border-left: 0;
    border-top: var(--border-thin) dashed var(--color-line);
  }

  .util-status {
    display: inline-flex;
  }

  .index-bar {
    top: 0;
  }
}

@media (max-width: 860px) {
  .grid--2,
  .grid--3 {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .shell {
    padding-inline: var(--space-2);
  }

  .section {
    padding-block: var(--space-6);
  }

  .section--lg {
    padding-block: var(--space-8);
  }

  .site-header__inner {
    gap: var(--space-1) var(--space-2);
  }

  .brand__mark {
    width: 40px;
    height: 40px;
    font-size: var(--text-base);
  }

  .brand__name {
    font-size: var(--text-base);
  }

  .site-footer {
    padding-top: var(--space-8);
  }

  .site-footer__brand {
    font-size: var(--text-2xl);
    margin-bottom: var(--space-4);
  }

  .site-footer__nav {
    flex-direction: column;
    gap: var(--space-2);
  }
}