:root {
  --color-surface: #2f2d32;
  --color-surface-alt: #3d3b41;
  --color-surface-deep: #4f4d53;
  --color-ink: #cfccd6;
  --color-ink-soft: #9c97ab;
  --color-ink-muted: #7f7990;
  --color-line: #4c4a50;
  --color-primary: #8969dd;
  --color-primary-ink: #131118;
  --color-primary-soft: #3c354a;
  --color-accent: #9ced12;
  --color-accent-ink: #131118;
  --color-highlight: #43502c;
  --color-focus: #9ffa05;
  --color-contrast-surface: #f4f4f6;
  --color-contrast-ink: #37353b;
  --color-contrast-line: #cacacd;
  --color-contrast-accent: #517b09;
  --overlay-scrim: linear-gradient(180deg, rgba(244, 244, 246, 0.35) 0%, rgba(244, 244, 246, 0.72) 55%, rgba(244, 244, 246, 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: 10.4px;
  --text-sm: 13.9px;
  --text-base: 16px;
  --text-lg: 21.3px;
  --text-xl: 28.4px;
  --text-2xl: 37.9px;
  --text-3xl: 50.5px;
  --text-4xl: 67.3px;
  --text-display: clamp(39px, 8.0vw, 102px);
  --text-figure: clamp(32px, 5.7vw, 73px);
  --weight-heading: 739;
  --weight-body: 400;
  --leading-body: 1.8;
  --leading-heading: 1.17;
  --tracking-heading: -0.013em;
  --radius-sm: 10px;
  --radius-md: 14px;
  --radius-lg: 18px;
  --radius-pill: 999px;
  --border-thin: 1px;
  --border-thick: 2px;
  --shadow-1: 0 0 0 1px rgba(156, 237, 18, 0.35);
  --shadow-2: 0 0 28px rgba(156, 237, 18, 0.35);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1180px;
  --measure: 71ch;
  --gutter: 16px;
  --section-y: 73px;
  --section-y-lg: 102px;
}

/* ===== reset ===== */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  background-color: var(--color-surface);
  background-image:
    radial-gradient(118% 78% at 90% -14%, color-mix(in srgb, var(--color-primary) 30%, transparent), transparent 62%),
    radial-gradient(80% 56% at 2% 8%, color-mix(in srgb, var(--color-primary) 16%, transparent), transparent 60%),
    linear-gradient(168deg, var(--color-surface) 0%, color-mix(in srgb, var(--color-surface) 74%, var(--color-primary-ink)) 100%);
  background-attachment: fixed;
  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: 0.012em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, svg, video { display: block; max-width: 100%; }
a { color: inherit; }
button { font: inherit; color: inherit; }
ul, ol { margin: 0; padding: 0; list-style: none; }
p { margin: 0 0 var(--space-2); }
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);
  text-wrap: balance;
}
h1 { font-size: var(--text-3xl); }
h2 { font-size: var(--text-xl); }
h3 { font-size: var(--text-lg); }
hr { border: 0; border-top: var(--border-thin) solid color-mix(in srgb, var(--color-line) 90%, transparent); margin: var(--space-4) 0; }
::selection { background: color-mix(in srgb, var(--color-primary) 55%, transparent); color: var(--color-ink); }

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

/* ===== 页面骨架避让 ===== */
@media (min-width: 1024px) { body { padding-left: 248px; } }
@media (max-width: 1023px) { body { padding-top: 62px; } }

/* ===== 容器与栅格 ===== */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--space-3);
}
.grid { display: grid; gap: var(--space-2); }
.grid--12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }
.stack { display: flex; flex-direction: column; gap: var(--space-2); }
.prose { max-width: var(--measure); }
@media (max-width: 900px) { .grid--12 { grid-template-columns: repeat(6, minmax(0, 1fr)); } }
@media (max-width: 600px) { .grid--12 { grid-template-columns: repeat(2, minmax(0, 1fr)); } }

/* ===== 章节与色块分隔 ===== */
.section { padding-block: var(--section-y); }
.section--lg { padding-block: var(--section-y-lg); }
.section--alt { background: color-mix(in srgb, var(--color-surface-alt) 72%, transparent); }
.section--contrast {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}
.section--contrast h1,
.section--contrast h2,
.section--contrast h3,
.section--contrast h4 { color: var(--color-contrast-ink); }
.section--contrast p,
.section--contrast li { color: color-mix(in srgb, var(--color-contrast-ink) 88%, transparent); }
.section--contrast .panel {
  background: color-mix(in srgb, var(--color-contrast-surface) 82%, var(--color-contrast-line));
  border-color: var(--color-contrast-line);
  box-shadow: 0 1px 0 color-mix(in srgb, var(--color-contrast-ink) 8%, transparent);
  color: var(--color-contrast-ink);
}
.section--contrast .figure,
.section--contrast .stat-value,
.section--contrast .tag--accent { color: var(--color-contrast-accent); }
.section--contrast .stat-label,
.section--contrast .tag { color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent); }

/* 超大章节编号 */
.section-index {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-display);
  line-height: 0.86;
  font-weight: 700;
  letter-spacing: -0.05em;
  font-variant-numeric: tabular-nums;
  color: color-mix(in srgb, var(--color-primary) 68%, transparent);
  margin: 0 0 var(--space-2);
  text-shadow: 0 0 34px color-mix(in srgb, var(--color-primary) 45%, transparent);
}
.section--contrast .section-index { color: color-mix(in srgb, var(--color-contrast-ink) 26%, transparent); text-shadow: none; }

/* ===== 发光面板 ===== */
.panel {
  position: relative;
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 42%, transparent);
  background:
    linear-gradient(158deg,
      color-mix(in srgb, var(--color-surface-deep) 90%, transparent) 0%,
      color-mix(in srgb, var(--color-surface-alt) 84%, transparent) 100%);
  box-shadow:
    0 0 0 1px color-mix(in srgb, var(--color-primary) 18%, transparent),
    0 0 22px color-mix(in srgb, var(--color-primary) 16%, transparent),
    inset 0 1px 0 color-mix(in srgb, var(--color-ink) 9%, transparent);
  transition: border-color 0.22s ease, box-shadow 0.22s ease;
}
.panel:hover {
  border-color: color-mix(in srgb, var(--color-primary) 72%, transparent);
  box-shadow:
    0 0 0 1px color-mix(in srgb, var(--color-primary) 34%, transparent),
    0 0 30px color-mix(in srgb, var(--color-primary) 26%, transparent),
    inset 0 1px 0 color-mix(in srgb, var(--color-ink) 12%, transparent);
}

/* ===== 数值与状态 ===== */
.figure {
  font-family: var(--font-mono);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
}
.stat { display: flex; flex-direction: column; gap: 4px; }
.stat-value {
  font-family: var(--font-mono);
  font-size: var(--text-2xl);
  font-weight: 700;
  line-height: 1.06;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  color: var(--color-accent);
}
.stat-label {
  font-size: var(--text-xs);
  letter-spacing: 0.18em;
  color: var(--color-ink-muted);
}
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 11px;
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 42%, transparent);
  background: color-mix(in srgb, var(--color-primary-soft) 74%, transparent);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  color: var(--color-ink-soft);
}
.tag--accent {
  border-color: color-mix(in srgb, var(--color-accent) 48%, transparent);
  background: color-mix(in srgb, var(--color-highlight) 70%, transparent);
  color: var(--color-accent);
}

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: 11px var(--space-3);
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 55%, transparent);
  background: color-mix(in srgb, var(--color-primary-soft) 66%, transparent);
  color: var(--color-ink);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.05em;
  text-decoration: none;
  cursor: pointer;
  transition: border-color 0.2s ease, background 0.2s ease, box-shadow 0.2s ease, transform 0.2s ease;
}
.btn:hover {
  border-color: var(--color-focus);
  box-shadow: 0 0 0 1px color-mix(in srgb, var(--color-focus) 40%, transparent);
  transform: translateY(-1px);
}
.btn--primary {
  background: var(--color-primary);
  border-color: color-mix(in srgb, var(--color-primary) 90%, transparent);
  color: var(--color-primary-ink);
  box-shadow: 0 0 20px color-mix(in srgb, var(--color-primary) 34%, transparent);
}
.btn--primary:hover {
  background: color-mix(in srgb, var(--color-primary) 88%, var(--color-accent));
  border-color: var(--color-focus);
  color: var(--color-primary-ink);
}
.btn--block { width: 100%; }

/* ===== 面包屑 ===== */
.breadcrumbs { font-size: var(--text-xs); letter-spacing: 0.1em; color: var(--color-ink-muted); }
.breadcrumbs ol { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; }
.breadcrumbs li { display: inline-flex; align-items: center; gap: 6px; }
.breadcrumbs li + li::before { content: "/"; color: color-mix(in srgb, var(--color-line) 90%, transparent); }
.breadcrumbs a { color: var(--color-ink-soft); text-decoration: none; }
.breadcrumbs a:hover { color: var(--color-accent); }

/* ===== 图片容器 ===== */
.media-frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border-radius: var(--radius-md);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 38%, transparent);
  background: color-mix(in srgb, var(--color-surface-deep) 72%, transparent);
  box-shadow: inset 0 0 24px color-mix(in srgb, var(--color-primary-ink) 55%, transparent);
}
.media-frame--4x3 { aspect-ratio: 4 / 3; }
.media-frame--1x1 { aspect-ratio: 1 / 1; }
.media-frame > img { width: 100%; height: 100%; object-fit: cover; }
.media-frame--grid::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(to right, color-mix(in srgb, var(--color-primary) 22%, transparent) 0 1px, transparent 1px 64px),
    repeating-linear-gradient(to bottom, color-mix(in srgb, var(--color-primary) 22%, transparent) 0 1px, transparent 1px 64px);
}
.media-frame--scrim::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 2;
  background: var(--overlay-scrim);
}
.media-caption {
  position: absolute;
  left: var(--space-2);
  right: var(--space-2);
  bottom: var(--space-2);
  z-index: 3;
  margin: 0;
  font-size: var(--text-sm);
  line-height: 1.5;
  color: var(--color-contrast-ink);
}
.media-caption .figure { color: var(--color-contrast-accent); }

/* ===== 标签页 ===== */
.tabs { display: flex; flex-wrap: wrap; gap: var(--space-1); }
.tab {
  padding: 8px var(--space-2);
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-line) 90%, transparent);
  background: transparent;
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: color 0.2s ease, border-color 0.2s ease, background 0.2s ease;
}
.tab:hover { color: var(--color-ink); border-color: color-mix(in srgb, var(--color-primary) 55%, transparent); }
.tab[aria-selected="true"] {
  color: var(--color-ink);
  border-color: color-mix(in srgb, var(--color-primary) 72%, transparent);
  background: color-mix(in srgb, var(--color-primary) 22%, transparent);
  box-shadow: 0 0 16px color-mix(in srgb, var(--color-primary) 24%, transparent);
}
.tab-panel[hidden] { display: none; }

/* ===== 显现动效 ===== */
[data-reveal] { transition: opacity 0.32s ease, transform 0.32s ease; }
[data-reveal].is-hidden { opacity: 0; transform: translateY(14px); }

/* ===== 头部：侧边轨道 ===== */
.skip-link {
  position: fixed;
  top: var(--space-2);
  left: 50%;
  z-index: 200;
  padding: 10px var(--space-3);
  border-radius: var(--radius-pill);
  background: var(--color-accent);
  color: var(--color-accent-ink);
  font-size: var(--text-sm);
  font-weight: 700;
  text-decoration: none;
  transform: translate(-50%, -220%);
  transition: transform 0.2s ease;
}
.skip-link:focus { transform: translate(-50%, 0); }

.site-header {
  position: fixed;
  z-index: 120;
  inset: 0 auto 0 0;
  width: 248px;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  padding: var(--space-4) var(--space-3);
  overflow-y: auto;
  background:
    linear-gradient(198deg,
      color-mix(in srgb, var(--color-surface-deep) 96%, transparent) 0%,
      color-mix(in srgb, var(--color-surface) 94%, transparent) 100%);
  border-right: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 42%, transparent);
  box-shadow: 2px 0 28px color-mix(in srgb, var(--color-primary) 18%, transparent);
  backdrop-filter: blur(6px);
}

.scroll-progress {
  position: absolute;
  top: 0;
  right: 0;
  width: var(--border-thick);
  height: 100%;
  background: linear-gradient(180deg, var(--color-accent) 0%, var(--color-primary) 100%);
  transform: scaleY(var(--progress, 0));
  transform-origin: top;
  box-shadow: 0 0 12px color-mix(in srgb, var(--color-accent) 55%, transparent);
}

.rail-brand { padding-bottom: var(--space-2); border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-line) 85%, transparent); }
.brand { display: flex; align-items: center; gap: var(--space-2); text-decoration: none; }
.brand-mark {
  position: relative;
  flex: none;
  width: 34px;
  height: 34px;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--color-primary) 0%, color-mix(in srgb, var(--color-primary) 45%, var(--color-accent)) 100%);
  box-shadow: 0 0 16px color-mix(in srgb, var(--color-primary) 58%, transparent);
}
.brand-mark::after {
  content: "";
  position: absolute;
  inset: 9px 7px;
  border-radius: 2px;
  background: var(--color-primary-ink);
  transform: skewX(-16deg);
  opacity: 0.88;
}
.brand-text { display: flex; flex-direction: column; gap: 2px; min-width: 0; }
.brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  letter-spacing: var(--tracking-heading);
  line-height: 1.2;
  color: var(--color-ink);
}
.brand-tag {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.22em;
  color: var(--color-ink-muted);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  padding: 8px 14px;
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 55%, transparent);
  background: color-mix(in srgb, var(--color-primary-soft) 70%, transparent);
  color: var(--color-ink);
  font-size: var(--text-sm);
  letter-spacing: 0.12em;
  cursor: pointer;
}
.nav-toggle-bars {
  position: relative;
  width: 16px;
  height: 10px;
  background:
    linear-gradient(var(--color-accent), var(--color-accent)) 0 0 / 100% var(--border-thick) no-repeat,
    linear-gradient(var(--color-ink-soft), var(--color-ink-soft)) 0 50% / 100% var(--border-thin) no-repeat,
    linear-gradient(var(--color-ink-soft), var(--color-ink-soft)) 0 100% / 100% var(--border-thin) no-repeat;
}
.nav-toggle-label { line-height: 1; }

.site-nav { display: block; }
.nav-list { display: flex; flex-direction: column; gap: 3px; }
.nav-item { display: block; }
.nav-link {
  position: relative;
  display: block;
  padding: 11px var(--space-2) 11px 26px;
  border-radius: var(--radius-sm);
  border: var(--border-thin) solid transparent;
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  text-decoration: none;
  transition: color 0.2s ease, background 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}
.nav-link::before {
  content: "";
  position: absolute;
  left: 10px;
  top: 50%;
  width: 5px;
  height: var(--border-thin);
  background: color-mix(in srgb, var(--color-ink-muted) 75%, transparent);
  transform: translateY(-50%);
  transition: width 0.2s ease, background 0.2s ease, box-shadow 0.2s ease;
}
.nav-link:hover {
  color: var(--color-ink);
  background: color-mix(in srgb, var(--color-primary-soft) 62%, transparent);
  border-color: color-mix(in srgb, var(--color-primary) 34%, transparent);
}
.nav-link:hover::before { width: 11px; background: var(--color-accent); }
.nav-link[aria-current="page"] {
  color: var(--color-ink);
  background: color-mix(in srgb, var(--color-primary) 24%, transparent);
  border-color: color-mix(in srgb, var(--color-primary) 62%, transparent);
  box-shadow: 0 0 18px color-mix(in srgb, var(--color-primary) 30%, transparent);
}
.nav-link[aria-current="page"]::before {
  width: 15px;
  background: var(--color-accent);
  box-shadow: 0 0 9px var(--color-accent);
}

.rail-foot {
  margin-top: auto;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding-top: var(--space-3);
  border-top: var(--border-thin) solid color-mix(in srgb, var(--color-line) 85%, transparent);
}
.rail-status {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}
.pulse {
  flex: none;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--color-accent);
  box-shadow: var(--shadow-2);
  animation: pulse-breathe 2.8s ease-in-out infinite;
}
@keyframes pulse-breathe {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.45; transform: scale(0.78); }
}

/* ===== 移动端头部：抽屉 ===== */
@media (max-width: 1023px) {
  .site-header {
    inset: 0 0 auto 0;
    width: auto;
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-2);
    padding: 14px var(--space-3);
    overflow: visible;
    border-right: 0;
    border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 45%, transparent);
    box-shadow: 0 6px 26px color-mix(in srgb, var(--color-primary-ink) 62%, transparent);
  }
  .rail-brand { padding-bottom: 0; border-bottom: 0; }
  .brand-name { font-size: var(--text-base); }
  .brand-tag { display: none; }
  .nav-toggle { display: inline-flex; }
  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: none;
    max-height: calc(100vh - 62px);
    overflow-y: auto;
    padding: var(--space-3);
    background: color-mix(in srgb, var(--color-surface-deep) 97%, transparent);
    border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 50%, transparent);
    box-shadow: 0 26px 44px color-mix(in srgb, var(--color-primary-ink) 72%, transparent);
  }
  .site-header[data-open] .site-nav { display: block; }
  .site-header[data-open] .nav-toggle {
    border-color: var(--color-focus);
    box-shadow: 0 0 0 1px color-mix(in srgb, var(--color-focus) 40%, transparent);
  }
  .nav-link { padding: 13px var(--space-3) 13px 26px; font-size: var(--text-base); }
  .rail-foot { display: none; }
  .scroll-progress {
    top: auto;
    right: 0;
    bottom: calc(-1 * var(--border-thick));
    left: 0;
    width: 100%;
    height: var(--border-thick);
    transform: scaleX(var(--progress, 0));
    transform-origin: left;
  }
}

/* ===== 页脚 ===== */
.site-footer {
  margin-top: var(--section-y-lg);
  padding-block: var(--section-y) var(--space-4);
  border-top: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 38%, transparent);
  background: linear-gradient(180deg,
    color-mix(in srgb, var(--color-surface) 94%, transparent) 0%,
    color-mix(in srgb, var(--color-surface) 62%, var(--color-primary-ink)) 100%);
}
.footer-brand {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-4);
  padding-bottom: var(--space-3);
  margin-bottom: var(--space-3);
  border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-line) 85%, transparent);
}
.brand--footer .brand-name { font-size: var(--text-xl); }
.footer-note {
  margin: 0;
  font-size: var(--text-xs);
  line-height: 1.7;
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}
.footer-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--space-2);
}
.footer-panel { padding: var(--space-3); }
.footer-panel--columns { grid-column: span 5; }
.footer-panel--tempo { grid-column: span 4; }
.footer-panel--contact { grid-column: span 3; }
.footer-panel--legal { grid-column: span 12; display: flex; flex-wrap: wrap; align-items: center; gap: var(--space-2) var(--space-4); }
.footer-panel--legal .footer-title { width: 100%; margin-bottom: var(--space-1); }
.footer-title {
  margin: 0 0 var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.24em;
  color: var(--color-ink-muted);
}
.footer-cols { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: var(--space-2); }
.footer-col { min-width: 0; }
.footer-k {
  display: block;
  margin: 0 0 6px;
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
}
.footer-link {
  display: block;
  padding: 4px 0;
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  color: var(--color-ink-soft);
  text-decoration: none;
  transition: color 0.2s ease;
}
.footer-link:hover { color: var(--color-accent); }
.footer-tempo { display: flex; flex-direction: column; }
.footer-row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 4px var(--space-2);
  margin: 0;
  padding: var(--space-1) 0;
  border-bottom: var(--border-thin) dashed color-mix(in srgb, var(--color-line) 85%, transparent);
}
.footer-tempo .footer-row:last-child { border-bottom: 0; }
.footer-row .footer-k { margin: 0; }
.footer-v {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.01em;
  color: var(--color-ink);
  word-break: break-word;
}
.footer-contact .footer-row { flex-direction: column; align-items: flex-start; gap: 2px; }
.footer-legal-links { display: flex; flex-wrap: wrap; gap: var(--space-3); }
.footer-legal-links .footer-link { padding: 0; }
.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-1) var(--space-3);
  margin-top: var(--space-4);
  padding-top: var(--space-2);
  border-top: var(--border-thin) solid color-mix(in srgb, var(--color-line) 85%, transparent);
}

/* ===== 返回顶部 ===== */
.to-top {
  position: fixed;
  right: var(--space-3);
  bottom: var(--space-3);
  z-index: 90;
  width: 46px;
  height: 46px;
  display: grid;
  place-items: center;
  border-radius: var(--radius-md);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 58%, transparent);
  background: color-mix(in srgb, var(--color-surface-deep) 92%, transparent);
  box-shadow: var(--shadow-1);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity 0.24s ease, transform 0.24s ease, visibility 0.24s ease, border-color 0.2s ease;
}
.to-top.is-visible { opacity: 1; visibility: visible; transform: none; }
.to-top:hover { border-color: var(--color-focus); }
.to-top-mark {
  width: 12px;
  height: 12px;
  border-left: var(--border-thick) solid var(--color-accent);
  border-top: var(--border-thick) solid var(--color-accent);
  transform: rotate(45deg) translate(2px, 2px);
}

/* ===== 响应式页脚 ===== */
@media (max-width: 1023px) {
  .footer-panel--columns { grid-column: span 12; }
  .footer-panel--tempo { grid-column: span 6; }
  .footer-panel--contact { grid-column: span 6; }
}
@media (max-width: 640px) {
  .footer-cols { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-panel--tempo,
  .footer-panel--contact { grid-column: span 12; }
  .footer-panel { padding: var(--space-2); }
  .footer-base { flex-direction: column; align-items: flex-start; }
}

/* ===== 降级动效 ===== */
@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;
  }
  [data-reveal].is-hidden { opacity: 1; transform: none; }
}