:root {
  --color-surface: #fdfdfd;
  --color-surface-alt: #f3f3f3;
  --color-surface-deep: #e5e5e5;
  --color-ink: #393234;
  --color-ink-soft: #695e61;
  --color-ink-muted: #857a7d;
  --color-line: #dad8d9;
  --color-primary: #d62959;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #f8dfe6;
  --color-accent: #e70d4b;
  --color-accent-ink: #ffffff;
  --color-highlight: #f9d2dd;
  --color-focus: #e40141;
  --color-contrast-surface: #201115;
  --color-contrast-ink: #e7e4e5;
  --color-contrast-line: #4c3f43;
  --color-contrast-accent: #f2265f;
  --overlay-scrim: linear-gradient(180deg, rgba(32, 17, 21, 0.35) 0%, rgba(32, 17, 21, 0.72) 55%, rgba(32, 17, 21, 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: 13.6px;
  --text-sm: 17.0px;
  --text-base: 19px;
  --text-lg: 23.8px;
  --text-xl: 29.7px;
  --text-2xl: 37.1px;
  --text-3xl: 46.4px;
  --text-4xl: 58.0px;
  --text-display: clamp(34px, 6.0vw, 77px);
  --text-figure: clamp(28px, 4.3vw, 55px);
  --weight-heading: 792;
  --weight-body: 400;
  --leading-body: 1.87;
  --leading-heading: 1.28;
  --tracking-heading: 0.002em;
  --radius-sm: 2px;
  --radius-md: 3px;
  --radius-lg: 4px;
  --radius-pill: 4px;
  --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: 1140px;
  --measure: 65ch;
  --gutter: 32px;
  --section-y: 96px;
  --section-y-lg: 134px;
}

/* ============================================================
   1. Reset 与基础排版
   ============================================================ */
*,
*::before,
*::after { box-sizing: border-box; }

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

body {
  margin: 0;
  background-color: 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 {
  margin: 0 0 var(--space-2);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

h1 { font-size: var(--text-2xl); }
h2 { font-size: var(--text-xl); }
h3 { font-size: var(--text-lg); }
h4 { font-size: var(--text-base); }

p { margin: 0 0 var(--space-3); }

ul, ol { margin: 0 0 var(--space-3); padding-inline-start: 1.25em; }

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

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

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

button { font: inherit; color: inherit; }

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

hr {
  border: 0;
  border-top: 1px solid var(--color-line);
  margin-block: var(--space-4);
}

main { display: block; }

::selection {
  background: var(--color-highlight);
  color: var(--color-ink);
}

a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible,
summary:focus-visible,
[tabindex]:focus-visible {
  outline: var(--border-thick) solid var(--color-focus);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* ============================================================
   2. 布局工具
   ============================================================ */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--space-3);
}

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

.grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--gutter);
  align-items: start;
}

.col-4 { grid-column: span 12; }
.col-8 { grid-column: span 12; }
.col-12 { grid-column: span 12; }

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

.rule-top { border-top: 1px solid var(--color-line); }
.rule-top--primary { border-top: var(--border-thin) solid var(--color-primary); }

.tick-strip {
  height: 10px;
  border-block: 1px solid var(--color-line);
  background-image: repeating-linear-gradient(90deg, var(--color-line) 0 1px, transparent 1px 24px);
  background-size: 24px 100%;
}

/* ============================================================
   3. 深色对比区块（唯一的反相方案）
   ============================================================ */
.slab {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-block: var(--border-thick) solid var(--color-primary);
  padding-block: var(--section-y-lg);
}

.slab h1, .slab h2, .slab h3, .slab h4 { color: var(--color-contrast-ink); }
.slab p { color: var(--color-contrast-ink); }
.slab a { color: var(--color-contrast-accent); }
.slab a:hover { color: var(--color-contrast-ink); }
.slab .section-num { color: var(--color-contrast-accent); }
.slab .section-kicker { color: var(--color-contrast-ink); opacity: 0.78; }
.slab .tick-strip {
  border-color: var(--color-contrast-line);
  background-image: repeating-linear-gradient(90deg, var(--color-contrast-line) 0 1px, transparent 1px 24px);
}
.slab .btn {
  background: transparent;
  border-color: var(--color-contrast-ink);
  color: var(--color-contrast-ink);
}
.slab .btn:hover {
  background: transparent;
  border-color: var(--color-contrast-accent);
  color: var(--color-contrast-accent);
}
.slab .btn--primary {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
}
.slab .btn--primary:hover {
  background: var(--color-contrast-accent);
  border-color: var(--color-contrast-accent);
  color: var(--color-contrast-surface);
}

/* ============================================================
   4. 章节头与编号强调
   ============================================================ */
.section-head {
  display: grid;
  gap: var(--space-1);
  margin-bottom: var(--space-6);
}

.section-num {
  font-family: var(--font-mono);
  font-size: var(--text-3xl);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  color: var(--color-primary);
  transition: color 140ms ease-out;
}

.section-title {
  margin: 0;
  font-size: var(--text-2xl);
  text-decoration: underline;
  text-decoration-color: transparent;
  text-decoration-thickness: var(--border-thick);
  text-underline-offset: 8px;
  transition: text-decoration-color 140ms ease-out;
}

.section-kicker {
  margin: 0;
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-ink-soft);
}

[data-section] { position: relative; }

[data-section][data-active] .section-num { color: var(--color-accent); }
[data-section][data-active] .section-title { text-decoration-color: var(--color-primary); }

.slab[data-section][data-active] .section-num { color: var(--color-contrast-accent); }
.slab[data-section][data-active] .section-title { text-decoration-color: var(--color-contrast-accent); }

.lede {
  max-width: var(--measure);
  font-size: var(--text-lg);
  line-height: 1.6;
  color: var(--color-ink-soft);
}

.prose { max-width: var(--measure); }
.prose h2 {
  margin-top: var(--space-6);
  font-size: var(--text-xl);
}
.prose h3 {
  margin-top: var(--space-4);
  font-size: var(--text-lg);
}
.prose p, .prose li { font-size: var(--text-base); }
.prose ul, .prose ol { margin-bottom: var(--space-4); }
.prose blockquote {
  margin: var(--space-4) 0;
  padding: var(--space-2) 0 var(--space-2) var(--space-3);
  border-inline-start: var(--border-thin) solid var(--color-primary);
  color: var(--color-ink-soft);
}

/* ============================================================
   5. 通用组件
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: 12px 20px;
  border: var(--border-thin) solid var(--color-ink);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
  cursor: pointer;
  box-shadow: none;
}

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

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

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

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

.btn--block { width: 100%; }

.breadcrumb { margin-block: var(--space-3); }

.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.breadcrumb-item + .breadcrumb-item::before {
  content: "/";
  margin-inline-end: 6px;
  color: var(--color-line);
}

.breadcrumb-list a {
  color: var(--color-ink-soft);
  font-weight: 600;
  text-decoration: none;
}

.breadcrumb-list a:hover {
  color: var(--color-primary);
  text-decoration: underline;
}

.breadcrumb-item[aria-current="page"] {
  color: var(--color-ink);
  font-weight: 600;
}

.tab-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin: 0 0 var(--space-3);
  padding: 0;
  list-style: none;
}

.tab {
  display: inline-block;
  padding: 10px 16px;
  border: var(--border-thin) solid var(--color-ink-soft);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
  cursor: pointer;
}

.tab:hover {
  border-color: var(--color-primary);
  background-color: var(--color-primary-soft);
  color: var(--color-primary);
}

.tab[aria-selected="true"],
.tab[aria-current="page"],
.tab.is-active {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
}

.chip-set {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin: 0;
  padding: 0;
  list-style: none;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  border: var(--border-thin) solid var(--color-ink-soft);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
  cursor: pointer;
}

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

.chip[aria-pressed="true"] {
  background-color: var(--color-contrast-surface);
  border-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.status {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-ink-soft);
}

.status-mark {
  width: 11px;
  height: 11px;
  flex: none;
  border: var(--border-thin) solid currentColor;
  border-radius: 1px;
  background-color: transparent;
}

.status--live { color: var(--color-primary); }
.status--live .status-mark { background-color: currentColor; }

.status--pending { color: var(--color-ink-soft); }
.status--pending .status-mark { background-image: linear-gradient(135deg, currentColor 0 45%, transparent 45% 100%); }

.status--void { color: var(--color-ink-muted); }
.status--void .status-mark { background-color: transparent; }

.data-table {
  width: 100%;
  font-size: var(--text-sm);
  font-variant-numeric: tabular-nums;
}

.data-table caption {
  padding-block: var(--space-1);
  text-align: start;
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.data-table th,
.data-table td {
  padding: 12px var(--space-2);
  border-bottom: 1px solid var(--color-line);
  text-align: start;
  vertical-align: top;
}

.data-table thead th {
  border-bottom: var(--border-thin) solid var(--color-ink);
  font-family: var(--font-heading);
  font-weight: 600;
}

.data-table tbody tr:nth-child(even) { background-color: var(--color-surface-alt); }

.data-table .num {
  font-family: var(--font-mono);
  text-align: end;
}

/* ============================================================
   6. 图片容器基础（页面阶段放置图片使用）
   ============================================================ */
.media {
  position: relative;
  display: block;
  overflow: hidden;
  margin: 0;
  background-color: var(--color-surface-deep);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
}

.media > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 0;
}

.media--16x9 { aspect-ratio: 16 / 9; }
.media--4x3 { aspect-ratio: 4 / 3; }
.media--3x4 { aspect-ratio: 3 / 4; }
.media--square { aspect-ratio: 1 / 1; }
.media--wide { aspect-ratio: 21 / 9; }

.media-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-scrim .media-caption,
.media-caption {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.5;
  color: var(--color-contrast-ink);
}

.media-scrim .media-title {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  color: var(--color-contrast-ink);
}

/* ============================================================
   7. 顶部阅读进度
   ============================================================ */
.progress-rail {
  position: fixed;
  inset-block-start: 0;
  inset-inline-start: 0;
  width: 100%;
  height: 3px;
  z-index: 90;
  background-color: transparent;
  pointer-events: none;
}

.progress-fill {
  height: 100%;
  width: 0;
  background-color: var(--color-accent);
  transition: width 120ms linear;
}

/* ============================================================
   8. 站点头部
   ============================================================ */
.skip-link {
  position: absolute;
  inset-inline-start: var(--space-2);
  inset-block-start: -120px;
  z-index: 100;
  padding: 12px 20px;
  border: var(--border-thin) solid var(--color-ink);
  border-radius: var(--radius-sm);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  text-decoration: none;
}

.skip-link:focus {
  inset-block-start: var(--space-2);
  color: var(--color-primary-ink);
}

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

.header-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1) var(--space-4);
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-2) var(--space-3);
}

.brand-block {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
  margin-inline-end: auto;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: 1.2;
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
  text-decoration: none;
}

.brand::before {
  content: "";
  width: 12px;
  height: 12px;
  flex: none;
  background-color: var(--color-primary);
  border: var(--border-thin) solid var(--color-ink);
}

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

.brand-note {
  margin: 0 0 0 22px;
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--color-ink-muted);
}

.site-nav { display: block; }

.nav-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0 var(--space-3);
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav-link {
  display: inline-block;
  padding: 10px 2px;
  border-bottom: var(--border-thick) solid transparent;
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1.2;
  color: var(--color-ink-soft);
  text-decoration: none;
}

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

.nav-link[aria-current="page"] {
  color: var(--color-ink);
  border-bottom-color: var(--color-primary);
}

.header-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 18px;
  border: var(--border-thin) solid var(--color-primary);
  border-radius: var(--radius-sm);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1.2;
  white-space: nowrap;
  text-decoration: none;
}

.header-cta:hover {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  padding: 10px 14px;
  border: var(--border-thin) solid var(--color-ink);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1.2;
  cursor: pointer;
}

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

.nav-toggle-bar {
  display: block;
  width: 16px;
  height: 2px;
  background-color: currentColor;
}

.nav-toggle-label { display: inline-block; }

.axis-bar {
  background-color: var(--color-surface-alt);
  border-top: 1px solid var(--color-line);
}

.axis-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1) var(--space-2);
  max-width: var(--container);
  margin-inline: auto;
  padding: 10px var(--space-3);
}

.axis-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin: 0;
  padding: 0;
  list-style: none;
}

.axis-link {
  display: inline-block;
  padding: 6px 12px;
  border: var(--border-thin) solid var(--color-ink-muted);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-size: var(--text-xs);
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
}

.axis-link:hover {
  border-color: var(--color-primary);
  background-color: var(--color-primary-soft);
  color: var(--color-primary);
}

.axis-note {
  margin: 0;
  font-size: var(--text-xs);
  color: var(--color-ink-soft);
}

.utility-note {
  margin: 0 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  white-space: nowrap;
}

/* ============================================================
   9. 站点页脚
   ============================================================ */
.site-footer {
  background-color: var(--color-surface-alt);
  color: var(--color-ink);
  border-top: var(--border-thick) solid var(--color-primary);
}

.footer-inner {
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-6) var(--space-3) var(--space-4);
}

.footer-top {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: var(--space-2) var(--space-6);
  padding-bottom: var(--space-4);
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin-inline-end: auto;
}

.footer-brand-link {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  line-height: 1.15;
  color: var(--color-ink);
  text-decoration: none;
}

.footer-brand-link:hover { color: var(--color-primary); }

.footer-brand-note {
  margin: 0;
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--color-ink-muted);
}

.footer-scope {
  margin: 0;
  max-width: 46ch;
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-ink-soft);
}

.footer-blocks {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-4);
  padding-block: var(--space-4);
}

.footer-block {
  padding-top: var(--space-2);
  border-top: var(--border-thin) solid var(--color-primary);
}

.footer-block-title {
  margin: 0 0 var(--space-2);
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.14em;
  color: var(--color-ink-muted);
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  margin: 0;
  padding: 0;
  list-style: none;
}

.footer-links a {
  align-self: flex-start;
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-ink);
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--color-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.footer-text {
  margin: 0;
  max-width: 34ch;
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-ink-soft);
}

.footer-contact {
  padding-block: var(--space-4);
  border-top: 1px solid var(--color-line);
}

.footer-contact-line {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-2);
  margin: 0 0 var(--space-1);
  font-size: var(--text-sm);
  font-variant-numeric: tabular-nums;
  color: var(--color-ink);
}

.footer-label {
  flex: none;
  display: inline-block;
  min-width: 5.5em;
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-1) var(--space-4);
  padding-top: var(--space-3);
  border-top: 1px solid var(--color-line);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.footer-meta { margin: 0; }

.footer-icp {
  margin: 0;
  font-family: var(--font-mono);
  color: var(--color-ink-soft);
}

/* ============================================================
   10. 响应式
   ============================================================ */
@media (min-width: 900px) {
  .grid { align-items: start; }
  .col-4 { grid-column: span 4; }
  .col-8 { grid-column: span 8; }
  .col-12 { grid-column: span 12; }

  .section-head {
    grid-template-columns: minmax(88px, auto) 1fr;
    gap: var(--space-1) var(--space-4);
    align-items: start;
  }
  .section-head .section-num {
    grid-column: 1;
    grid-row: 1 / span 2;
  }
  .section-head .section-title,
  .section-head .section-kicker { grid-column: 2; }

  .offset-shift-left { margin-inline-start: calc(var(--gutter) * -1); }
  .offset-shift-right { margin-inline-start: var(--gutter); }
}

@media (max-width: 899px) {
  .nav-toggle { display: inline-flex; order: 3; }

  .brand-block { order: 1; }
  .header-cta { order: 2; padding: 8px 14px; font-size: var(--text-xs); }
  .brand-note { display: none; }

  .site-nav {
    order: 4;
    flex-basis: 100%;
    display: none;
    padding-top: var(--space-2);
    border-top: 1px solid var(--color-line);
  }

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

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .nav-link {
    display: block;
    padding: 14px 2px;
    border-bottom: 1px solid var(--color-line);
    border-inline-start: var(--border-thick) solid transparent;
    border-radius: 0;
    font-size: var(--text-base);
  }

  .nav-link:hover {
    border-bottom-color: var(--color-line);
    border-inline-start-color: var(--color-line);
    background-color: var(--color-surface-alt);
  }

  .nav-link[aria-current="page"] {
    border-bottom-color: var(--color-line);
    border-inline-start-color: var(--color-primary);
    background-color: var(--color-primary-soft);
  }

  .axis-bar { display: none; }

  .section { padding-block: var(--space-6); }
  .section--lg { padding-block: var(--space-8); }

  .footer-top { padding-bottom: var(--space-3); }
  .footer-scope { max-width: none; }
}

@media (max-width: 599px) {
  .header-inner { gap: var(--space-1) var(--space-2); }
  .brand { font-size: var(--text-base); }
  .brand::before { width: 10px; height: 10px; }
  .footer-brand-link { font-size: var(--text-lg); }
  .footer-blocks { grid-template-columns: 1fr; }
  .media--wide { aspect-ratio: 16 / 9; }
  .progress-rail { height: 4px; }
}

/* ============================================================
   11. 动效偏好
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }

  .progress-fill { transition: none; }
  .section-num,
  .section-title { transition: none; }
}