:root {
  --color-surface: #2c2b2f;
  --color-surface-alt: #3a393e;
  --color-surface-deep: #4c4b50;
  --color-ink: #ccc9d4;
  --color-ink-soft: #9a95a7;
  --color-ink-muted: #7e778d;
  --color-line: #49474d;
  --color-primary: #8d6bdb;
  --color-primary-ink: #131118;
  --color-primary-soft: #3a3447;
  --color-accent: #b9ef10;
  --color-accent-ink: #131118;
  --color-highlight: #454e29;
  --color-focus: #bffc03;
  --color-contrast-surface: #f0f0f2;
  --color-contrast-ink: #343338;
  --color-contrast-line: #c7c6c9;
  --color-contrast-accent: #5c7708;
  --overlay-scrim: linear-gradient(180deg, rgba(240, 240, 242, 0.35) 0%, rgba(240, 240, 242, 0.72) 55%, rgba(240, 240, 242, 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: 12.2px;
  --text-sm: 15.2px;
  --text-base: 17px;
  --text-lg: 21.2px;
  --text-xl: 26.6px;
  --text-2xl: 33.2px;
  --text-3xl: 41.5px;
  --text-4xl: 51.9px;
  --text-display: clamp(41px, 8.4vw, 107px);
  --text-figure: clamp(34px, 6.0vw, 77px);
  --weight-heading: 658;
  --weight-body: 400;
  --leading-body: 1.79;
  --leading-heading: 1.25;
  --tracking-heading: 0.0em;
  --radius-sm: 10px;
  --radius-md: 12px;
  --radius-lg: 13px;
  --radius-pill: 999px;
  --border-thin: 1px;
  --border-thick: 2px;
  --shadow-1: 0 0 0 1px rgba(185, 239, 16, 0.35);
  --shadow-2: 0 0 28px rgba(185, 239, 16, 0.35);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1120px;
  --measure: 74ch;
  --gutter: 32px;
  --section-y: 95px;
  --section-y-lg: 133px;
}

/* ============================================================
   1. Reset 与全局底纹
   ============================================================ */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 148px;
}

body {
  margin: 0;
  background-color: var(--color-surface);
  background-image:
    linear-gradient(to right, color-mix(in srgb, var(--color-line) 34%, transparent) var(--border-thin), transparent var(--border-thin)),
    linear-gradient(to bottom, color-mix(in srgb, var(--color-line) 34%, transparent) var(--border-thin), transparent var(--border-thin));
  background-size: 72px 72px, 72px 72px;
  background-position: center top, center top;
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  min-height: 100vh;
}

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

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

a { color: inherit; }

button { font: inherit; color: inherit; }

hr { border: 0; }

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

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

/* ============================================================
   2. 中文排版与文字层级
   ============================================================ */
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-3xl); }
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); }

strong, b { font-weight: 700; color: var(--color-ink); }

.display {
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: 0.92;
  letter-spacing: -0.02em;
  margin: 0 0 var(--space-3);
}

.figure {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 600;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  color: var(--color-accent);
  margin: 0 0 var(--space-1);
}

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

.eyebrow {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
  margin: 0 0 var(--space-1);
}

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

/* ============================================================
   3. 布局容器与栅格
   ============================================================ */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: clamp(var(--space-2), 4vw, var(--gutter));
}

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

.col-3 { grid-column: span 3; }
.col-4 { grid-column: span 4; }
.col-5 { grid-column: span 5; }
.col-6 { grid-column: span 6; }
.col-7 { grid-column: span 7; }
.col-8 { grid-column: span 8; }
.col-12 { grid-column: span 12; }

.stack { display: grid; gap: var(--space-2); }

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

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

.section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-1) var(--space-3);
  margin-bottom: var(--space-4);
}

.section__head h2 { margin: 0; }

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

.prose p,
.prose li { color: var(--color-ink); }

.prose ul,
.prose ol { display: grid; gap: var(--space-1); margin: 0 0 var(--space-2); padding-left: var(--space-3); list-style: disc; }

/* 错位边界分隔语言 */
.divider {
  position: relative;
  display: block;
  width: 100%;
  height: var(--border-thin);
  background: var(--color-line);
  margin: var(--space-4) 0;
}

.divider--offset::after {
  content: "";
  position: absolute;
  left: 14%;
  top: calc(-1 * var(--border-thin));
  width: 72px;
  height: var(--border-thick);
  background: var(--color-accent);
}

.divider--offset-right::after { left: auto; right: 22%; }

/* ============================================================
   4. 面板、标签、反相区块
   ============================================================ */
.panel {
  position: relative;
  background: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  padding: var(--space-3);
}

.panel--glow {
  border-color: color-mix(in srgb, var(--color-primary) 58%, transparent);
  box-shadow:
    0 0 0 1px color-mix(in srgb, var(--color-primary) 32%, transparent),
    0 0 26px color-mix(in srgb, var(--color-primary) 20%, transparent);
  transition: border-color 200ms ease, box-shadow 200ms ease;
}

.panel--glow:hover,
.panel--glow:focus-within {
  border-color: color-mix(in srgb, var(--color-accent) 62%, transparent);
  box-shadow:
    0 0 0 1px color-mix(in srgb, var(--color-accent) 34%, transparent),
    0 0 28px color-mix(in srgb, var(--color-accent) 22%, transparent);
}

.panel--deep {
  background: var(--color-surface-deep);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-1);
}

.panel--flat {
  background: transparent;
  border-color: var(--color-line);
  border-radius: var(--radius-sm);
}

.tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  background: var(--color-primary-soft);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 40%, transparent);
  color: var(--color-ink);
}

.block-contrast {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-radius: var(--radius-md);
  padding: var(--space-4);
  border: var(--border-thin) solid var(--color-contrast-line);
}

.block-contrast h2,
.block-contrast h3,
.block-contrast p,
.block-contrast li { color: var(--color-contrast-ink); }

.block-contrast .divider { background: var(--color-contrast-line); }

.block-contrast__num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--text-2xl);
  color: var(--color-contrast-accent);
  letter-spacing: -0.01em;
}

.block-contrast__label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: color-mix(in srgb, var(--color-contrast-ink) 68%, transparent);
}

/* ============================================================
   5. 按钮
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 12px 20px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-surface-alt);
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.02em;
  text-decoration: none;
  cursor: pointer;
  transition: border-color 180ms ease, box-shadow 180ms ease, color 180ms ease, background-color 180ms ease;
}

.btn:hover {
  border-color: color-mix(in srgb, var(--color-primary) 70%, transparent);
  box-shadow: 0 0 20px color-mix(in srgb, var(--color-primary) 26%, transparent);
}

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

.btn--primary:hover {
  background: color-mix(in srgb, var(--color-accent) 86%, var(--color-surface));
  box-shadow: var(--shadow-2);
  color: var(--color-accent-ink);
}

.btn--quiet {
  background: transparent;
  color: var(--color-ink-soft);
}

.btn--quiet:hover { color: var(--color-ink); }

/* ============================================================
   6. 面包屑 / 锚点目录
   ============================================================ */
.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
  padding-block: var(--space-3) 0;
}

.breadcrumbs li { display: inline-flex; align-items: center; gap: var(--space-1); }

.breadcrumbs li + li::before {
  content: "/";
  color: var(--color-line);
}

.breadcrumbs a { text-decoration: none; }

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

.toc {
  border-left: var(--border-thin) solid var(--color-line);
  padding-left: var(--space-2);
  display: grid;
  gap: 6px;
}

.toc a {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  text-decoration: none;
}

.toc a:hover,
.toc a[aria-current="true"] { color: var(--color-accent); }

/* ============================================================
   7. 图片容器（去边直角）
   ============================================================ */
.media {
  position: relative;
  display: block;
  margin: 0;
  border-radius: 0;
  overflow: hidden;
  background: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
}

.media img,
.media svg { width: 100%; height: 100%; object-fit: cover; }

.media--wide { aspect-ratio: 16 / 9; }
.media--tall { aspect-ratio: 3 / 4; }
.media--square { aspect-ratio: 1 / 1; }
.media--band { aspect-ratio: 21 / 9; }

.media__scrim {
  position: absolute;
  inset: 0;
  background: var(--overlay-scrim);
}

.media__caption {
  position: absolute;
  inset: auto 0 0 0;
  padding: var(--space-2) var(--space-3);
  background: var(--overlay-scrim);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  line-height: 1.5;
}

.media__caption .numeric { color: var(--color-contrast-accent); }

/* ============================================================
   8. 标签页 / 分段切换
   ============================================================ */
.tablist {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.tab {
  appearance: none;
  background: transparent;
  border: var(--border-thin) solid transparent;
  border-bottom: 0;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
  padding: 10px 16px;
  color: var(--color-ink-soft);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.02em;
  cursor: pointer;
  transition: color 180ms ease, background-color 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
}

.tab:hover { color: var(--color-ink); }

.tab[aria-selected="true"] {
  color: var(--color-accent);
  background: color-mix(in srgb, var(--color-accent) 8%, transparent);
  border-color: color-mix(in srgb, var(--color-accent) 45%, transparent);
  box-shadow: 0 0 18px color-mix(in srgb, var(--color-accent) 18%, transparent);
}

.tabpanel { padding-top: var(--space-3); }

.tabpanel[hidden] { display: none; }

/* ============================================================
   9. 扫描线 / 显现
   ============================================================ */
.scanline {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}

.scanline::after {
  content: "";
  position: absolute;
  inset-inline: -30%;
  top: 38%;
  height: var(--border-thin);
  background: linear-gradient(90deg, transparent, color-mix(in srgb, var(--color-accent) 70%, transparent), transparent);
  animation: scan-drift 9s linear infinite;
}

@keyframes scan-drift {
  0% { transform: translateY(-160px); opacity: 0; }
  20% { opacity: 0.85; }
  80% { opacity: 0.85; }
  100% { transform: translateY(220px); opacity: 0; }
}

.js [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 520ms ease, transform 520ms ease;
}

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

/* ============================================================
   10. 头部外壳
   ============================================================ */
.skip-link {
  position: absolute;
  left: var(--space-2);
  top: calc(-1 * var(--space-8));
  z-index: 120;
  padding: 10px 18px;
  background: var(--color-accent);
  color: var(--color-accent-ink);
  font-weight: 700;
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: top 180ms ease;
}

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

.scroll-progress {
  position: fixed;
  inset: 0 0 auto 0;
  height: var(--border-thick);
  transform: scaleX(0);
  transform-origin: left center;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  z-index: 90;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: color-mix(in srgb, var(--color-surface) 90%, transparent);
  backdrop-filter: blur(14px) saturate(140%);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.site-header::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: var(--border-thin);
  background: linear-gradient(90deg, var(--color-primary) 0%, var(--color-accent) 24%, transparent 62%);
  pointer-events: none;
}

.header-top { border-bottom: var(--border-thin) solid var(--color-line); }

.header-top__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  min-height: 58px;
  padding-block: var(--space-1);
}

.header-main__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  padding-block: 6px;
}

/* 品牌 */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--color-ink);
  flex: 0 0 auto;
}

.brand__mark {
  position: relative;
  width: 24px;
  height: 24px;
  flex: 0 0 auto;
  border: var(--border-thin) solid var(--color-accent);
  border-radius: var(--radius-sm);
  box-shadow: 0 0 14px color-mix(in srgb, var(--color-accent) 34%, transparent);
}

.brand__mark::after {
  content: "";
  position: absolute;
  inset: 5px;
  background: var(--color-accent);
  opacity: 0.86;
  border-radius: 2px;
}

.brand__name {
  display: block;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: 1.15;
  letter-spacing: 0.02em;
}

.brand__domain {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}

.brand--footer { margin-bottom: var(--space-2); }

/* 章节定位刻度 */
.tick-rail {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  flex: 1 1 auto;
  min-width: 0;
}

.tick {
  display: block;
  width: 26px;
  height: var(--border-thick);
  background: var(--color-line);
  flex: 0 0 auto;
}

.tick.is-on {
  background: var(--color-accent);
  box-shadow: 0 0 12px color-mix(in srgb, var(--color-accent) 55%, transparent);
}

.tick-rail__label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  color: var(--color-ink-muted);
  white-space: nowrap;
  margin-left: var(--space-1);
}

/* 全局快捷入口 */
.header-tools {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  flex: 0 0 auto;
}

.tool-link {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 92px;
  padding: 6px 12px;
  text-decoration: none;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background: color-mix(in srgb, var(--color-surface-alt) 72%, transparent);
  transition: border-color 180ms ease, box-shadow 180ms ease;
}

.tool-link__key {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--color-ink);
  line-height: 1.2;
}

.tool-link__val {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.04em;
  color: var(--color-ink-muted);
  line-height: 1.2;
  white-space: nowrap;
}

.tool-link:hover {
  border-color: color-mix(in srgb, var(--color-primary) 72%, transparent);
  box-shadow: 0 0 18px color-mix(in srgb, var(--color-primary) 26%, transparent);
}

.tool-link--accent { border-color: color-mix(in srgb, var(--color-accent) 40%, transparent); }

.tool-link--accent:hover {
  border-color: color-mix(in srgb, var(--color-accent) 70%, transparent);
  box-shadow: 0 0 20px color-mix(in srgb, var(--color-accent) 24%, transparent);
}

/* 主导航 */
.site-nav { flex: 1 1 auto; }

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

.nav-link {
  position: relative;
  display: block;
  padding: 9px 15px;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--color-ink-soft);
  text-decoration: none;
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-sm);
  transition: color 160ms ease, border-color 160ms ease, box-shadow 160ms ease, background-color 160ms ease;
}

.nav-link:hover {
  color: var(--color-ink);
  border-color: var(--color-line);
  background: color-mix(in srgb, var(--color-surface-alt) 80%, transparent);
}

.nav-link[aria-current="page"] {
  color: var(--color-accent);
  border-color: color-mix(in srgb, var(--color-accent) 52%, transparent);
  background: color-mix(in srgb, var(--color-accent) 7%, transparent);
  box-shadow: 0 0 16px color-mix(in srgb, var(--color-accent) 18%, transparent);
}

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  padding: 9px 14px;
  background: var(--color-surface-alt);
  color: var(--color-ink);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  font-weight: 600;
  cursor: pointer;
}

.nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  gap: 3px;
}

.nav-toggle__bars i {
  display: block;
  width: 16px;
  height: var(--border-thick);
  background: var(--color-ink-soft);
  transition: transform 180ms ease, background-color 180ms ease;
}

.site-header[data-open] .nav-toggle {
  border-color: color-mix(in srgb, var(--color-accent) 55%, transparent);
  color: var(--color-accent);
}

.site-header[data-open] .nav-toggle__bars i { background: var(--color-accent); }

.site-header[data-open] .nav-toggle__bars i:nth-child(1) { transform: translateY(5px) rotate(45deg); }
.site-header[data-open] .nav-toggle__bars i:nth-child(2) { opacity: 0; }
.site-header[data-open] .nav-toggle__bars i:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

/* ============================================================
   11. 页脚外壳
   ============================================================ */
.site-footer {
  position: relative;
  margin-top: var(--section-y-lg);
  background: var(--color-surface-alt);
  border-top: var(--border-thin) solid var(--color-line);
}

.site-footer::before {
  content: "";
  position: absolute;
  top: calc(-1 * var(--border-thin));
  left: 0;
  width: 38%;
  height: var(--border-thin);
  background: linear-gradient(90deg, var(--color-accent), transparent);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--space-4) var(--gutter);
  padding-block: var(--space-8) var(--space-4);
}

.footer-col { grid-column: span 2; }

.footer-col:not(.footer-col--brand) {
  border-top: var(--border-thin) solid var(--color-line);
}

.footer-col--brand {
  grid-column: span 3;
  padding-top: 0;
}

.footer-col--index {
  grid-column: span 3;
  padding-top: var(--space-2);
}

.footer-col--legal {
  grid-column: span 2;
  padding-top: var(--space-3);
}

.footer-col--rhythm {
  grid-column: span 2;
  padding-top: var(--space-1);
}

.footer-col--contact {
  grid-column: span 2;
  padding-top: var(--space-4);
}

.footer-col__title {
  margin: 0 0 var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.footer-list { display: grid; gap: 7px; }

.footer-list a {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  text-decoration: none;
  border-bottom: var(--border-thin) solid transparent;
  transition: color 160ms ease, border-color 160ms ease;
}

.footer-list a:hover {
  color: var(--color-accent);
  border-bottom-color: color-mix(in srgb, var(--color-accent) 60%, transparent);
}

.footer-meta { display: grid; gap: var(--space-1); }

.footer-meta li { display: grid; gap: 2px; }

.footer-meta__link {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-ink);
  text-decoration: none;
  border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-accent) 45%, transparent);
}

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

.footer-meta__k {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}

.footer-meta__v {
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-ink-soft);
}

.footer-note {
  margin: var(--space-2) 0 0;
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-ink-muted);
  max-width: 28ch;
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-1) var(--space-3);
  border-top: var(--border-thin) solid var(--color-line);
  padding-block: var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}

.footer-bottom__item { white-space: nowrap; }

/* ============================================================
   12. 响应式
   ============================================================ */
@media (max-width: 1024px) {
  html { scroll-padding-top: 132px; }

  .col-3, .col-4, .col-5, .col-6 { grid-column: span 6; }
  .col-7, .col-8 { grid-column: span 12; }

  .footer-col,
  .footer-col--legal,
  .footer-col--rhythm,
  .footer-col--contact { grid-column: span 6; padding-top: var(--space-2); }

  .footer-col--brand { grid-column: span 12; }
  .footer-col--index { grid-column: span 6; }
  .footer-col--legal { padding-top: var(--space-3); }
  .footer-col--rhythm { padding-top: var(--space-1); }
  .footer-col--contact { padding-top: var(--space-3); }

  .tick-rail { display: none; }
}

@media (max-width: 900px) {
  html { scroll-padding-top: 118px; }

  .header-top__inner { flex-wrap: wrap; gap: var(--space-1) var(--space-2); }

  .header-tools {
    width: 100%;
    overflow-x: auto;
    padding-bottom: var(--space-1);
    scrollbar-width: thin;
  }

  .tool-link { min-width: 78px; padding: 5px 10px; }

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

  .site-nav {
    display: none;
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    background: var(--color-surface-alt);
    border-top: var(--border-thin) solid var(--color-line);
    border-bottom: var(--border-thin) solid var(--color-line);
    box-shadow: 0 18px 40px color-mix(in srgb, var(--color-surface) 70%, transparent);
    padding: var(--space-2) clamp(var(--space-2), 4vw, var(--gutter)) var(--space-3);
  }

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

  .nav-list { flex-direction: column; align-items: stretch; gap: 2px; }

  .nav-link {
    padding: 12px 14px;
    font-size: var(--text-base);
    border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-line) 60%, transparent);
    border-radius: 0;
  }

  .nav-link[aria-current="page"] {
    border-radius: var(--radius-sm);
    border-bottom-color: color-mix(in srgb, var(--color-accent) 52%, transparent);
  }

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

@media (max-width: 640px) {
  .grid { grid-template-columns: repeat(6, minmax(0, 1fr)); gap: var(--space-3); }

  .col-3, .col-4, .col-5, .col-6, .col-7, .col-8, .col-12 { grid-column: span 6; }

  .footer-grid { grid-template-columns: repeat(6, minmax(0, 1fr)); }

  .footer-col,
  .footer-col--brand,
  .footer-col--index,
  .footer-col--legal,
  .footer-col--rhythm,
  .footer-col--contact {
    grid-column: span 6;
    padding-top: var(--space-2);
  }

  .footer-col--brand { padding-top: 0; }

  .tool-link__val { display: none; }
  .tool-link { min-width: 0; }

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

  .block-contrast { padding: var(--space-3); }
  .footer-note { max-width: none; }
}

/* ============================================================
   13. 无障碍与降低动效
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }

  .scanline::after { display: none; }

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

  .scroll-progress { transition: none; }
}