:root {
  --color-surface: #f8f8f8;
  --color-surface-alt: #efeff0;
  --color-surface-deep: #e2e3e4;
  --color-ink: #424952;
  --color-ink-soft: #656e7b;
  --color-ink-muted: #747e8b;
  --color-line: #d7d8da;
  --color-primary: #4376bc;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #dfe6f0;
  --color-accent: #098385;
  --color-accent-ink: #ffffff;
  --color-highlight: #cde3e3;
  --color-focus: #027b7d;
  --color-contrast-surface: #14191f;
  --color-contrast-ink: #e4e5e7;
  --color-contrast-line: #42464b;
  --color-contrast-accent: #11eaee;
  --overlay-scrim: linear-gradient(180deg, rgba(20, 25, 31, 0.35) 0%, rgba(20, 25, 31, 0.72) 55%, rgba(20, 25, 31, 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: 11.0px;
  --text-sm: 14.7px;
  --text-base: 17px;
  --text-lg: 22.7px;
  --text-xl: 30.2px;
  --text-2xl: 40.3px;
  --text-3xl: 53.7px;
  --text-4xl: 71.5px;
  --text-display: clamp(48px, 9.8vw, 126px);
  --text-figure: clamp(40px, 7.1vw, 91px);
  --weight-heading: 632;
  --weight-body: 400;
  --leading-body: 1.82;
  --leading-heading: 1.19;
  --tracking-heading: -0.0em;
  --radius-sm: 14px;
  --radius-md: 18px;
  --radius-lg: 22px;
  --radius-pill: 999px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: 0 6px 18px rgba(66, 73, 82, 0.08);
  --shadow-2: 0 18px 44px rgba(66, 73, 82, 0.14);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1160px;
  --measure: 72ch;
  --gutter: 16px;
  --section-y: 100px;
  --section-y-lg: 140px;
}

/* ============================================================
   1. reset 与底色层
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  color: var(--color-ink);
  background-color: var(--color-surface);
  overflow-x: hidden;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -2;
  pointer-events: none;
  background:
    radial-gradient(58vw 58vw at 6% 2%, color-mix(in srgb, var(--color-primary) 26%, transparent) 0%, transparent 64%),
    radial-gradient(50vw 50vw at 94% 16%, color-mix(in srgb, var(--color-accent) 18%, transparent) 0%, transparent 62%),
    radial-gradient(62vw 42vw at 64% 98%, color-mix(in srgb, var(--color-primary-soft) 92%, transparent) 0%, transparent 70%);
}

body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  opacity: 0.36;
  background-image:
    repeating-linear-gradient(0deg, color-mix(in srgb, var(--color-line) 60%, transparent) 0 1px, transparent 1px 64px),
    repeating-linear-gradient(90deg, color-mix(in srgb, var(--color-line) 60%, transparent) 0 1px, transparent 1px 64px);
}

h1, h2, h3, h4, h5 {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

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

p { margin: 0 0 var(--space-2); }

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

a { color: inherit; }

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

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
}

:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--color-focus) 70%, transparent);
  outline-offset: 3px;
}

/* ============================================================
   2. 排版与容器
   ============================================================ */
.shell {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.prose { max-width: var(--measure); }
.prose p { color: var(--color-ink-soft); }
.prose strong { color: var(--color-ink); }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
  margin: 0;
}

.eyebrow::before {
  content: "";
  width: 22px;
  height: 2px;
  border-radius: 2px;
  background: color-mix(in srgb, var(--color-accent) 76%, transparent);
}

.eyebrow--deep { color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent); }
.eyebrow--deep::before { background: var(--color-contrast-accent); }

.lede {
  font-size: var(--text-lg);
  line-height: 1.6;
  color: var(--color-ink-soft);
  max-width: 60ch;
}

.num {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  color: var(--color-accent);
}

.num--lg {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-3xl);
  line-height: 1;
  letter-spacing: 0.02em;
  color: color-mix(in srgb, var(--color-accent) 88%, transparent);
}

.hl {
  background-image: linear-gradient(180deg, transparent 56%, var(--color-highlight) 56%, var(--color-highlight) 94%, transparent 94%);
  background-repeat: no-repeat;
  padding: 0 2px;
}

/* ============================================================
   3. 刻度与分隔
   ============================================================ */
.scale {
  display: flex;
  align-items: flex-end;
  gap: 4px;
  height: 20px;
  margin: var(--space-3) 0;
}

.scale__tick {
  display: block;
  width: 1px;
  height: 8px;
  background: color-mix(in srgb, var(--color-ink-muted) 46%, transparent);
}

.scale__tick--tall {
  height: 20px;
  background: color-mix(in srgb, var(--color-accent) 82%, transparent);
}

.section--deep .scale__tick { background: color-mix(in srgb, var(--color-contrast-ink) 34%, transparent); }
.section--deep .scale__tick--tall { background: var(--color-contrast-accent); }

/* ============================================================
   4. 玻璃面板与卡片
   ============================================================ */
.panel {
  position: relative;
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-primary-ink) 66%, var(--color-line));
  background: color-mix(in srgb, var(--color-surface) 72%, transparent);
  -webkit-backdrop-filter: blur(14px) saturate(1.1);
  backdrop-filter: blur(14px) saturate(1.1);
  box-shadow: var(--shadow-1);
  transition: background-color 0.24s ease, border-color 0.24s ease, transform 0.24s ease, box-shadow 0.24s ease;
}

.panel--flat { box-shadow: none; }

.panel--deep {
  background: color-mix(in srgb, var(--color-contrast-surface) 55%, transparent);
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
}

.panel--link:hover,
.panel--link:focus-visible {
  background: color-mix(in srgb, var(--color-surface) 84%, transparent);
  border-color: color-mix(in srgb, var(--color-primary) 40%, transparent);
  transform: translateY(-3px);
  box-shadow: var(--shadow-2);
}

.card { padding: var(--space-4); }

.card__top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  margin-bottom: var(--space-3);
}

.card__title { font-size: var(--text-lg); margin-bottom: 8px; }

.card__text { font-size: var(--text-sm); color: var(--color-ink-soft); margin: 0; }

.card__foot {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px;
  margin-top: var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.04em;
  color: var(--color-ink-muted);
}

/* ============================================================
   5. 区块
   ============================================================ */
.section {
  position: relative;
  padding-block: var(--section-y);
}

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

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

.section--deep::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(44vw 44vw at 88% 6%, color-mix(in srgb, var(--color-primary) 40%, transparent) 0%, transparent 62%),
    radial-gradient(36vw 36vw at 4% 92%, color-mix(in srgb, var(--color-accent) 32%, transparent) 0%, transparent 64%);
}

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

.section--deep p,
.section--deep .lede,
.section--deep .section-sub { color: color-mix(in srgb, var(--color-contrast-ink) 80%, transparent); }

.section-head {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  max-width: 66ch;
  margin-bottom: var(--space-6);
}

.section-title { font-size: var(--text-2xl); }

.section-sub {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-body);
  color: var(--color-ink-soft);
  margin: 0;
}

/* ============================================================
   6. 栅格
   ============================================================ */
.grid {
  display: grid;
  gap: var(--space-3);
  grid-template-columns: repeat(12, minmax(0, 1fr));
}

.grid--2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid--3 { grid-template-columns: repeat(auto-fit, minmax(238px, 1fr)); }

.col-4 { grid-column: span 4; }
.col-6 { grid-column: span 6; }
.col-8 { grid-column: span 8; }

@media (max-width: 900px) {
  .col-4, .col-6, .col-8 { grid-column: 1 / -1; }
}

/* ============================================================
   7. 按钮
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  border: var(--border-thin) solid transparent;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: calc(var(--tracking-heading) + 0.05em);
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}

.btn--primary {
  background: var(--color-primary);
  color: var(--color-primary-ink);
  box-shadow: var(--shadow-1);
}

.btn--primary:hover {
  background: color-mix(in srgb, var(--color-primary) 84%, var(--color-contrast-surface));
  transform: translateY(-2px);
  box-shadow: var(--shadow-2);
}

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

.btn--accent:hover {
  background: color-mix(in srgb, var(--color-accent) 84%, var(--color-contrast-surface));
  transform: translateY(-2px);
}

.btn--ghost {
  background: color-mix(in srgb, var(--color-surface) 62%, transparent);
  border-color: color-mix(in srgb, var(--color-line) 96%, transparent);
  color: var(--color-ink);
}

.btn--ghost:hover {
  background: color-mix(in srgb, var(--color-surface) 84%, transparent);
  border-color: color-mix(in srgb, var(--color-primary) 38%, transparent);
  color: var(--color-primary);
  transform: translateY(-2px);
}

.section--deep .btn--ghost {
  background: color-mix(in srgb, var(--color-contrast-ink) 10%, transparent);
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
}

.section--deep .btn--ghost:hover {
  background: color-mix(in srgb, var(--color-contrast-ink) 18%, transparent);
  border-color: color-mix(in srgb, var(--color-contrast-accent) 50%, transparent);
  color: var(--color-contrast-accent);
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
  margin-top: var(--space-3);
}

/* ============================================================
   8. 状态徽章
   ============================================================ */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 11px;
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid transparent;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  white-space: nowrap;
  background: color-mix(in srgb, var(--color-surface-deep) 80%, transparent);
  color: var(--color-ink-muted);
}

.badge::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: currentColor;
}

.badge--live {
  background: color-mix(in srgb, var(--color-accent) 14%, transparent);
  border-color: color-mix(in srgb, var(--color-accent) 38%, transparent);
  color: var(--color-accent);
}

.badge--pending {
  background: color-mix(in srgb, var(--color-primary) 12%, transparent);
  border-color: color-mix(in srgb, var(--color-primary) 36%, transparent);
  color: var(--color-primary);
}

.badge--transit {
  background: color-mix(in srgb, var(--color-ink-muted) 14%, transparent);
  border-color: color-mix(in srgb, var(--color-ink-muted) 30%, transparent);
  color: var(--color-ink-soft);
}

.badge--quarter {
  background: color-mix(in srgb, var(--color-contrast-surface) 92%, transparent);
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-accent);
}

/* ============================================================
   9. 图片容器（页面阶段放置）
   ============================================================ */
.media {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-lg);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-primary-ink) 58%, var(--color-line));
  background: var(--color-surface-deep);
  box-shadow: var(--shadow-1);
  isolation: isolate;
}

.media__img,
.media > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  aspect-ratio: 16 / 9;
}

.media--tall .media__img,
.media--tall > img { aspect-ratio: 4 / 5; }

.media__scrim {
  position: absolute;
  inset: 0;
  background: var(--overlay-scrim);
  pointer-events: none;
}

.media__overlay {
  position: absolute;
  inset: auto 0 0 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: var(--space-3) var(--space-4);
  color: var(--color-contrast-ink);
}

.media__title {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  letter-spacing: calc(var(--tracking-heading) + 0.03em);
  color: var(--color-contrast-ink);
}

.media__text {
  font-size: var(--text-sm);
  color: color-mix(in srgb, var(--color-contrast-ink) 84%, transparent);
  margin: 0;
}

/* ============================================================
   10. 面包屑
   ============================================================ */
.breadcrumbs { padding-top: var(--space-3); }

.breadcrumbs__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}

.breadcrumbs__link {
  text-decoration: none;
  color: var(--color-ink-soft);
  border-bottom: 1px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.breadcrumbs__link:hover {
  color: var(--color-primary);
  border-color: color-mix(in srgb, var(--color-primary) 50%, transparent);
}

.breadcrumbs__sep { color: var(--color-line); }

.breadcrumbs__item[aria-current="page"] { color: var(--color-ink); }

/* ============================================================
   11. 状态筛选
   ============================================================ */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  width: fit-content;
  max-width: 100%;
  padding: 8px;
  border-radius: var(--radius-lg);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-primary-ink) 60%, var(--color-line));
  background: color-mix(in srgb, var(--color-surface) 64%, transparent);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-1);
}

.filter-chip {
  padding: 8px 15px;
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid transparent;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  letter-spacing: calc(var(--tracking-heading) + 0.04em);
  color: var(--color-ink-soft);
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.filter-chip:hover {
  color: var(--color-ink);
  background: color-mix(in srgb, var(--color-surface-alt) 88%, transparent);
}

.filter-chip.is-active,
.filter-chip[aria-pressed="true"] {
  background: var(--color-primary);
  color: var(--color-primary-ink);
  border-color: color-mix(in srgb, var(--color-primary) 60%, transparent);
}

.is-hidden { display: none !important; }

/* ============================================================
   12. 章节索引条（由 JS 生成）
   ============================================================ */
.chapter-rail {
  position: fixed;
  right: 16px;
  top: 50%;
  transform: translateY(-50%);
  z-index: 50;
  display: none;
}

@media (min-width: 1240px) {
  .chapter-rail { display: block; }
}

.chapter-rail__list {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 8px;
}

.chapter-rail__link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 10px;
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid transparent;
  text-decoration: none;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
  background: color-mix(in srgb, var(--color-surface) 58%, transparent);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  transition: color 0.2s ease, border-color 0.2s ease, background-color 0.2s ease;
}

.chapter-rail__num { color: var(--color-accent); }

.chapter-rail__mark {
  max-width: 0;
  overflow: hidden;
  white-space: nowrap;
  opacity: 0;
  transition: max-width 0.24s ease, opacity 0.24s ease;
}

.chapter-rail__link:hover,
.chapter-rail__link:focus-visible { color: var(--color-ink); }

.chapter-rail__link:hover .chapter-rail__mark,
.chapter-rail__link:focus-visible .chapter-rail__mark,
.chapter-rail__link[aria-current="true"] .chapter-rail__mark {
  max-width: 150px;
  opacity: 1;
}

.chapter-rail__link[aria-current="true"] {
  color: var(--color-primary);
  border-color: color-mix(in srgb, var(--color-primary) 34%, transparent);
  background: color-mix(in srgb, var(--color-surface) 84%, transparent);
}

/* ============================================================
   13. 滚动显现
   ============================================================ */
[data-reveal] { transition: opacity 0.34s ease, transform 0.34s ease; }

.js [data-reveal] {
  opacity: 0;
  transform: translateY(12px);
}

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

/* ============================================================
   14. 头部
   ============================================================ */
.skip-link {
  position: absolute;
  left: var(--space-2);
  top: -72px;
  z-index: 140;
  padding: 12px 18px;
  border-radius: var(--radius-sm);
  background: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.05em;
  text-decoration: none;
  transition: top 0.18s ease;
}

.skip-link:focus { top: var(--space-2); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 90;
  color: var(--color-ink);
  background: color-mix(in srgb, var(--color-surface) 78%, transparent);
  -webkit-backdrop-filter: blur(18px) saturate(1.16);
  backdrop-filter: blur(18px) saturate(1.16);
  border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-line) 92%, transparent);
  box-shadow: inset 0 1px 0 color-mix(in srgb, var(--color-primary-ink) 70%, transparent);
}

.header-shell {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  min-height: 72px;
  padding-block: 10px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  padding: 4px 6px;
  margin-left: -6px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  border: var(--border-thin) solid transparent;
  transition: border-color 0.2s ease, background-color 0.2s ease;
}

.brand:hover {
  border-color: color-mix(in srgb, var(--color-line) 90%, transparent);
  background: color-mix(in srgb, var(--color-surface) 60%, transparent);
}

.brand__mark {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  flex: 0 0 auto;
  border-radius: var(--radius-sm);
  background: linear-gradient(150deg, var(--color-primary), color-mix(in srgb, var(--color-accent) 68%, var(--color-primary)));
  color: var(--color-primary-ink);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  box-shadow: var(--shadow-1);
}

.brand__text {
  display: flex;
  flex-direction: column;
  gap: 3px;
  line-height: 1.15;
}

.brand__name {
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: var(--weight-heading);
  letter-spacing: calc(var(--tracking-heading) + 0.04em);
}

.brand__line {
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-soft);
}

.nav { margin-inline: auto; }

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

.nav__item { display: block; }

.nav__link {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding: 9px 12px;
  border-radius: var(--radius-sm);
  border: var(--border-thin) solid transparent;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  letter-spacing: calc(var(--tracking-heading) + 0.04em);
  text-decoration: none;
  color: var(--color-ink-soft);
  transition: color 0.2s ease, background-color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

.nav__idx {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.02em;
  color: var(--color-ink-muted);
  transition: color 0.2s ease;
}

.nav__link:hover {
  color: var(--color-ink);
  background: color-mix(in srgb, var(--color-surface-alt) 76%, transparent);
  border-color: color-mix(in srgb, var(--color-line) 92%, transparent);
  transform: translateY(-2px);
}

.nav__link:hover .nav__idx { color: var(--color-accent); }

.nav__link[aria-current="page"] {
  color: var(--color-primary);
  background: color-mix(in srgb, var(--color-primary-soft) 84%, transparent);
  border-color: color-mix(in srgb, var(--color-primary) 34%, transparent);
}

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

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
}

.header-cta { white-space: nowrap; }

.nav-toggle {
  display: none;
  align-items: center;
  gap: 9px;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-line) 94%, transparent);
  background: color-mix(in srgb, var(--color-surface) 70%, transparent);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  color: var(--color-ink);
  transition: background-color 0.2s ease, border-color 0.2s ease;
}

.nav-toggle:hover {
  background: color-mix(in srgb, var(--color-surface) 88%, transparent);
  border-color: color-mix(in srgb, var(--color-primary) 34%, transparent);
}

.nav-toggle__bars {
  position: relative;
  display: block;
  width: 18px;
  height: 12px;
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: transform 0.22s ease;
}

.nav-toggle__bars::before { top: 0; }
.nav-toggle__bars::after { bottom: 0; }

.site-header[data-open="true"] .nav-toggle__bars::before { transform: translateY(5px) rotate(45deg); }
.site-header[data-open="true"] .nav-toggle__bars::after { transform: translateY(-5px) rotate(-45deg); }

.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  overflow: hidden;
  background: color-mix(in srgb, var(--color-line) 55%, transparent);
}

.scroll-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--color-primary) 0%, var(--color-accent) 62%, var(--color-contrast-accent) 100%);
}

/* ============================================================
   15. 页脚
   ============================================================ */
.site-footer {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  margin-top: var(--section-y-lg);
  padding-block: var(--space-8) var(--space-4);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.site-footer::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(46vw 46vw at 90% 4%, color-mix(in srgb, var(--color-primary) 44%, transparent) 0%, transparent 62%),
    radial-gradient(38vw 38vw at 4% 92%, color-mix(in srgb, var(--color-accent) 34%, transparent) 0%, transparent 64%);
}

.footer-shell { position: relative; }

.footer-top {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 1.15fr);
  gap: var(--space-8);
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  align-items: flex-start;
}

.footer-tagline {
  font-size: var(--text-2xl);
  line-height: var(--leading-heading);
  color: var(--color-contrast-ink);
  max-width: 22ch;
}

.footer-contact {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-contact__item {
  display: grid;
  grid-template-columns: 78px minmax(0, 1fr);
  gap: 12px;
  align-items: baseline;
  font-size: var(--text-sm);
}

.footer-contact__label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: color-mix(in srgb, var(--color-contrast-ink) 56%, transparent);
}

.footer-contact__link {
  color: var(--color-contrast-ink);
  text-decoration: none;
  border-bottom: var(--border-thin) solid var(--color-contrast-line);
  padding-bottom: 2px;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.footer-contact__link:hover {
  color: var(--color-contrast-accent);
  border-color: var(--color-contrast-accent);
}

.footer-contact__text {
  color: color-mix(in srgb, var(--color-contrast-ink) 82%, transparent);
}

.footer-cols {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--space-4);
  padding-top: var(--space-1);
}

.footer-col__title {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--weight-body);
  letter-spacing: 0.14em;
  color: color-mix(in srgb, var(--color-contrast-ink) 58%, transparent);
  margin-bottom: var(--space-2);
}

.footer-col__list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-col__link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: var(--text-sm);
  text-decoration: none;
  color: var(--color-contrast-ink);
  transition: color 0.2s ease;
}

.footer-col__link::before {
  content: "";
  width: 6px;
  height: 1px;
  background: var(--color-contrast-line);
  transition: width 0.2s ease, background-color 0.2s ease;
}

.footer-col__link:hover { color: var(--color-contrast-accent); }

.footer-col__link:hover::before {
  width: 15px;
  background: var(--color-contrast-accent);
}

.footer-mark {
  margin: var(--space-8) 0 var(--space-4);
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: 0.92;
  letter-spacing: 0.02em;
  color: color-mix(in srgb, var(--color-contrast-ink) 20%, transparent);
  user-select: none;
}

@supports ((-webkit-background-clip: text) or (background-clip: text)) {
  .footer-mark {
    background-image: linear-gradient(100deg,
      color-mix(in srgb, var(--color-contrast-ink) 34%, transparent) 0%,
      color-mix(in srgb, var(--color-contrast-accent) 62%, transparent) 96%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
  }
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-2);
  padding-top: var(--space-3);
  border-top: var(--border-thin) solid var(--color-contrast-line);
  font-size: var(--text-xs);
  color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent);
}

.footer-base__text { margin: 0; }

.footer-base__text--mono {
  font-family: var(--font-mono);
  letter-spacing: 0.08em;
}

.footer-note {
  margin: var(--space-2) 0 0;
  max-width: 66ch;
  font-size: var(--text-xs);
  line-height: 1.7;
  color: color-mix(in srgb, var(--color-contrast-ink) 52%, transparent);
}

/* ============================================================
   16. 响应式
   ============================================================ */
@media (max-width: 1080px) {
  .brand__line { display: none; }
  .nav__link { padding: 9px 10px; }
}

@media (max-width: 960px) {
  :root { --section-y: 72px; --section-y-lg: 96px; }

  html { scroll-padding-top: 84px; }

  .nav-toggle { display: inline-flex; }

  .nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    margin: 0;
    padding: var(--space-3) var(--gutter) var(--space-4);
    display: block;
    background: color-mix(in srgb, var(--color-surface) 96%, transparent);
    -webkit-backdrop-filter: blur(20px) saturate(1.12);
    backdrop-filter: blur(20px) saturate(1.12);
    border-bottom: var(--border-thin) solid var(--color-line);
    box-shadow: var(--shadow-2);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity 0.22s ease, transform 0.22s ease, visibility 0.22s;
  }

  .site-header[data-open="true"] .nav {
    opacity: 1;
    visibility: visible;
    transform: none;
  }

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

  .nav__link {
    width: 100%;
    justify-content: flex-start;
    padding: 13px 14px;
    font-size: var(--text-base);
    background: color-mix(in srgb, var(--color-surface) 62%, transparent);
    border-color: color-mix(in srgb, var(--color-line) 80%, transparent);
  }

  .nav__link:hover { transform: none; }

  .footer-top {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--space-6);
  }

  .footer-cols { padding-top: 0; }
}

@media (max-width: 700px) {
  .header-shell { min-height: 64px; gap: var(--space-2); }
  .brand__mark { width: 34px; height: 34px; }
  .brand__name { font-size: var(--text-sm); }
  .nav-toggle__label { display: none; }
  .nav-toggle { padding: 11px 12px; }
  .footer-cols { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-3); }
  .footer-contact__item { grid-template-columns: minmax(0, 1fr); gap: 4px; }
  .footer-tagline { font-size: var(--text-xl); }
  .filter-bar { width: 100%; }
}

@media (max-width: 420px) {
  .header-cta { padding: 11px 14px; }
}

/* ============================================================
   17. 降低动态效果
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

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

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

  .nav__link:hover,
  .btn:hover,
  .panel--link:hover { transform: none; }
}