:root {
  --color-surface: #292729;
  --color-surface-alt: #383538;
  --color-surface-deep: #49464a;
  --color-ink: #cbc2cc;
  --color-ink-soft: #9e8e9f;
  --color-ink-muted: #877788;
  --color-line: #464346;
  --color-primary: #b14fb5;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #3c2d3d;
  --color-accent: #73da25;
  --color-accent-ink: #181118;
  --color-highlight: #364728;
  --color-focus: #71e718;
  --color-contrast-surface: #f6f5f6;
  --color-contrast-ink: #383338;
  --color-contrast-line: #cccacc;
  --color-contrast-accent: #437e15;
  --overlay-scrim: linear-gradient(180deg, rgba(246, 245, 246, 0.35) 0%, rgba(246, 245, 246, 0.72) 55%, rgba(246, 245, 246, 0.92) 100%);
  --font-heading: STZhongsong, "Source Han Serif SC", "Songti SC", SimSun, serif;
  --font-body: "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, Menlo, Consolas, monospace;
  --text-xs: 10.1px;
  --text-sm: 14.3px;
  --text-base: 17px;
  --text-lg: 24.0px;
  --text-xl: 34.0px;
  --text-2xl: 48.1px;
  --text-3xl: 68.0px;
  --text-4xl: 96.1px;
  --text-display: clamp(47px, 9.7vw, 124px);
  --text-figure: clamp(39px, 7.0vw, 89px);
  --weight-heading: 652;
  --weight-body: 400;
  --leading-body: 1.84;
  --leading-heading: 1.2;
  --tracking-heading: 0.004em;
  --radius-sm: 7px;
  --radius-md: 10px;
  --radius-lg: 13px;
  --radius-pill: 999px;
  --border-thin: 1px;
  --border-thick: 2px;
  --shadow-1: 0 6px 18px rgba(203, 194, 204, 0.08);
  --shadow-2: 0 18px 44px rgba(203, 194, 204, 0.14);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1180px;
  --measure: 66ch;
  --gutter: 16px;
  --section-y: 95px;
  --section-y-lg: 133px;
}

/* ============================================================
   1. Reset 与基础排版
   ============================================================ */
*,
*::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(circle at 86% -8%, color-mix(in srgb, var(--color-primary) 22%, transparent) 0%, transparent 44%),
    radial-gradient(circle at 2% 106%, color-mix(in srgb, var(--color-accent) 12%, transparent) 0%, transparent 40%);
  background-repeat: no-repeat;
  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,
picture,
svg,
video,
canvas { display: block; max-width: 100%; }

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

h1, h2, h3, h4, h5 {
  margin: 0 0 var(--space-3);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: color-mix(in srgb, var(--color-ink) 80%, #ffffff);
}

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

ul, ol { margin: 0 0 var(--space-3); padding-left: 1.25em; }
li { margin-bottom: 6px; }

hr { border: 0; height: 0; }

a {
  color: var(--color-primary);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
a:hover { color: var(--color-accent); }

strong, b {
  font-weight: 700;
  color: color-mix(in srgb, var(--color-ink) 82%, #ffffff);
}

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

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

#main-content {
  display: block;
  scroll-margin-top: 96px;
}

/* ============================================================
   2. 布局辅助
   ============================================================ */
.wrap {
  width: min(100% - (var(--space-4) * 2), var(--container));
  margin-inline: auto;
}

.wrap--tight {
  width: min(100% - (var(--space-4) * 2), 860px);
  margin-inline: auto;
}

.prose { max-width: var(--measure); }
.prose p,
.prose li { color: var(--color-ink); }
.prose p + h2,
.prose p + h3 { margin-top: var(--space-6); }
.prose h2 { font-size: var(--text-xl); }
.prose h3 { font-size: var(--text-lg); }

.lead {
  max-width: var(--measure);
  font-size: var(--text-lg);
  line-height: 1.62;
  color: var(--color-ink-soft);
}

.section { padding-block: var(--section-y); }
.section--lg { padding-block: var(--section-y-lg); }
.section--tint { background-color: color-mix(in srgb, var(--color-surface-alt) 55%, var(--color-surface)); }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-accent);
}
.eyebrow::before {
  content: "";
  flex: none;
  width: 24px;
  height: var(--border-thick);
  background-color: var(--color-accent);
}

.section-title {
  margin-bottom: var(--space-3);
  font-size: var(--text-2xl);
}
.section-title em {
  font-style: normal;
  color: var(--color-primary);
}

.rule {
  margin-block: var(--space-6);
  border-top: var(--border-thick) solid var(--color-line);
}
.rule--double {
  height: 5px;
  border-top: var(--border-thin) solid var(--color-line);
  border-bottom: var(--border-thin) solid var(--color-line);
}
.rule--primary { border-top-color: var(--color-primary); }

/* ============================================================
   3. 通用组件
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 10px var(--space-2);
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-sm);
  background-color: var(--color-surface-alt);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 700;
  line-height: 1.35;
  letter-spacing: 0.04em;
  text-align: center;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 150ms ease, color 150ms ease, border-color 150ms ease, box-shadow 150ms ease;
}
.btn:hover {
  background-color: color-mix(in srgb, var(--color-surface-alt) 76%, var(--color-primary));
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
}
.btn-primary {
  background-color: var(--color-primary);
  border-color: color-mix(in srgb, var(--color-primary) 62%, #ffffff);
  color: var(--color-primary-ink);
}
.btn-primary:hover {
  background-color: color-mix(in srgb, var(--color-primary) 84%, #ffffff);
  border-color: color-mix(in srgb, var(--color-primary) 48%, #ffffff);
  color: var(--color-primary-ink);
  box-shadow: var(--shadow-2);
}
.btn-ghost {
  background-color: transparent;
  border-color: var(--color-line);
  color: var(--color-ink-soft);
}
.btn-ghost:hover {
  background-color: color-mix(in srgb, var(--color-primary) 16%, transparent);
  border-color: var(--color-primary);
  color: color-mix(in srgb, var(--color-ink) 78%, #ffffff);
}
.btn-accent {
  background-color: var(--color-accent);
  border-color: color-mix(in srgb, var(--color-accent) 60%, #ffffff);
  color: var(--color-accent-ink);
}
.btn-accent:hover {
  background-color: color-mix(in srgb, var(--color-accent) 86%, #ffffff);
  color: var(--color-accent-ink);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 10px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-pill);
  background-color: var(--color-surface-deep);
  color: var(--color-ink-soft);
  font-size: var(--text-xs);
  line-height: 1.6;
  letter-spacing: 0.08em;
  white-space: nowrap;
}
.tag--accent {
  background-color: var(--color-accent);
  border-color: color-mix(in srgb, var(--color-accent) 55%, #ffffff);
  color: var(--color-accent-ink);
  font-weight: 700;
}
.tag--primary {
  background-color: var(--color-primary);
  border-color: color-mix(in srgb, var(--color-primary) 55%, #ffffff);
  color: var(--color-primary-ink);
}

.panel {
  position: relative;
  padding: var(--space-3);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  background-color: var(--color-surface-alt);
  box-shadow: var(--shadow-1);
}
.panel--soft {
  background-color: var(--color-primary-soft);
  border-color: color-mix(in srgb, var(--color-line) 55%, var(--color-primary));
}
.panel--contrast {
  background-color: var(--color-contrast-surface);
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
  box-shadow: var(--shadow-2);
}
.panel--contrast h2,
.panel--contrast h3,
.panel--contrast h4 { color: var(--color-contrast-ink); }
.panel--contrast p,
.panel--contrast li { color: var(--color-contrast-ink); }
.panel--contrast a { color: var(--color-contrast-accent); }
.panel--contrast a:hover { color: var(--color-primary); }
.panel--flush { padding: 0; overflow: hidden; }

.figure-num {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 800;
  line-height: 0.9;
  letter-spacing: -0.02em;
  color: var(--color-accent);
  font-variant-numeric: tabular-nums;
}
.panel--contrast .figure-num { color: var(--color-contrast-accent); }

.figure-unit {
  margin-left: 0.25em;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--color-ink-soft);
}
.panel--contrast .figure-unit { color: color-mix(in srgb, var(--color-contrast-ink) 68%, transparent); }

.num {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--color-accent);
  font-variant-numeric: tabular-nums;
}
.num--ink { color: var(--color-ink); }

.media {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
  background-color: var(--color-surface-alt);
}
.media--wide { aspect-ratio: 21 / 9; }
.media--tall { aspect-ratio: 4 / 5; }
.media--square { aspect-ratio: 1 / 1; }
.media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media-scrim {
  position: absolute;
  inset: 0;
  background-image: var(--overlay-scrim);
  pointer-events: none;
}
.media-body {
  position: absolute;
  inset: auto 0 0 0;
  z-index: 2;
  padding: var(--space-3);
  color: var(--color-contrast-ink);
}
.media-body h3 {
  margin-bottom: var(--space-1);
  font-size: var(--text-lg);
  color: var(--color-contrast-ink);
}
.media-body p {
  margin-bottom: 0;
  color: var(--color-contrast-ink);
}

.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: var(--space-4);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}
.breadcrumbs a {
  color: var(--color-ink-soft);
  text-decoration: none;
}
.breadcrumbs a:hover { color: var(--color-accent); }
.breadcrumbs span { color: var(--color-ink-muted); }

.skip-link {
  position: fixed;
  top: -140px;
  left: var(--space-3);
  z-index: 200;
  padding: 12px 18px;
  border-radius: var(--radius-sm);
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: 0.06em;
  text-decoration: none;
  transition: top 140ms ease;
}
.skip-link:focus {
  top: var(--space-3);
  color: var(--color-accent-ink);
}

/* ============================================================
   4. 头部：桌面端左侧轨道 / 移动端顶部条 + 抽屉
   ============================================================ */
.site-header {
  position: relative;
  z-index: 80;
  background-color: color-mix(in srgb, var(--color-surface) 86%, #000000);
}

.header-rail {
  padding: var(--space-2) 0
}

.rail-brand {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  min-width: 0;
  color: inherit;
  text-decoration: none;
}
.brand:hover { color: inherit; }

.brand-glyph {
  flex: none;
  width: 26px;
  height: 26px;
  border-radius: var(--radius-sm);
  background-image: linear-gradient(135deg, var(--color-primary) 0%, color-mix(in srgb, var(--color-accent) 62%, var(--color-primary)) 100%);
  box-shadow:
    inset 0 0 0 1px color-mix(in srgb, var(--color-primary-ink) 46%, transparent),
    0 0 18px color-mix(in srgb, var(--color-primary) 45%, transparent);
}

.brand-copy {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}
.brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: var(--weight-heading);
  line-height: 1.15;
  letter-spacing: 0.03em;
  color: color-mix(in srgb, var(--color-ink) 84%, #ffffff);
}
.brand-sub {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 9px 12px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface-alt);
  color: var(--color-ink);
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: 0.1em;
  cursor: pointer;
  transition: border-color 150ms ease, color 150ms ease;
}
.nav-toggle:hover {
  border-color: var(--color-primary);
  color: color-mix(in srgb, var(--color-ink) 78%, #ffffff);
}
.nav-toggle-icon {
  position: relative;
  display: block;
  width: 14px;
  height: 2px;
  background-color: currentColor;
}
.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: "";
  position: absolute;
  left: 0;
  width: 14px;
  height: 2px;
  background-color: currentColor;
  transition: transform 160ms ease;
}
.nav-toggle-icon::before { top: -5px; }
.nav-toggle-icon::after { top: 5px; }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon { background-color: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon::before { transform: translateY(5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon::after { transform: translateY(-5px) rotate(-45deg); }

.rail-status {
  margin: var(--space-2) 0 0;
  padding: 8px var(--space-2);
  border: var(--border-thin) solid var(--color-line);
  border-left: var(--border-thick) solid var(--color-accent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  background-color: var(--color-surface-deep);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.7;
  letter-spacing: 0.06em;
  color: var(--color-ink-soft);
}

.site-nav { margin-top: var(--space-2); }

.nav-list {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.nav-item { margin: 0; }

.nav-link {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  padding: 10px var(--space-2);
  border-left: var(--border-thick) solid transparent;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--color-ink);
  text-decoration: none;
  transition: background-color 140ms ease, color 140ms ease, border-color 140ms ease;
}
.nav-link:hover {
  background-color: var(--color-surface-alt);
  border-left-color: var(--color-primary);
  color: color-mix(in srgb, var(--color-ink) 80%, #ffffff);
}
.nav-link[aria-current="page"] {
  background-color: var(--color-highlight);
  border-left-color: var(--color-accent);
  color: color-mix(in srgb, var(--color-ink) 88%, #ffffff);
}
.nav-link[aria-current="page"] .nav-index { color: var(--color-accent); }

.nav-index {
  flex: none;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}
.nav-label {
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
}

.rail-foot { margin-top: var(--space-2); }

.rail-actions {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.rail-progress {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  width: 2px;
  background-color: color-mix(in srgb, var(--color-line) 70%, transparent);
  overflow: hidden;
}
.rail-progress-fill {
  display: block;
  width: 100%;
  height: 0;
  background-color: var(--color-accent);
  box-shadow: 0 0 12px color-mix(in srgb, var(--color-accent) 60%, transparent);
}

/* ============================================================
   5. 页脚
   ============================================================ */
.site-footer {
  position: relative;
  margin-top: var(--section-y);
  border-top: var(--border-thick) solid var(--color-line);
  background-color: color-mix(in srgb, var(--color-surface) 86%, #000000);
}
.site-footer::before {
  content: "";
  position: absolute;
  top: 3px;
  left: 0;
  right: 0;
  height: var(--border-thin);
  background-color: var(--color-line);
  opacity: 0.6;
  pointer-events: none;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1) var(--space-3);
  width: min(100% - (var(--space-4) * 2), var(--container));
  margin-inline: auto;
  padding: var(--space-3) 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

.footer-brand {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  color: var(--color-ink-soft);
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}
.footer-links a {
  padding-bottom: 1px;
  border-bottom: var(--border-thin) solid transparent;
  color: var(--color-ink-soft);
  text-decoration: none;
  transition: color 140ms ease, border-color 140ms ease;
}
.footer-links a:hover {
  border-bottom-color: var(--color-accent);
  color: var(--color-accent);
}

.footer-contact { color: var(--color-ink-muted); }

.footer-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-3);
  margin-left: auto;
}
.footer-icp { color: var(--color-ink-muted); }
.footer-copy { color: var(--color-ink-muted); }

.to-top {
  position: fixed;
  right: var(--space-3);
  bottom: var(--space-3);
  z-index: 70;
  display: none;
  align-items: center;
  gap: 6px;
  padding: 10px 16px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-pill);
  background-color: color-mix(in srgb, var(--color-surface-alt) 92%, transparent);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.12em;
  cursor: pointer;
  box-shadow: var(--shadow-1);
  transition: border-color 150ms ease, color 150ms ease, background-color 150ms ease;
}
.to-top[data-visible="true"] { display: inline-flex; }
.to-top:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* ============================================================
   6. 显现协议
   ============================================================ */
.js [data-reveal] {
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 120ms ease-out, transform 120ms ease-out;
}
.js [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

/* ============================================================
   7. 响应式
   ============================================================ */
@media (max-width: 1023px) {
  .site-header {
    position: sticky;
    top: 0;
    z-index: 90;
    border-bottom: var(--border-thin) solid var(--color-line);
    background-color: color-mix(in srgb, var(--color-surface) 93%, #000000);
  }
  .header-rail {
    width: min(100% - (var(--space-4) * 2), var(--container));
    margin-inline: auto;
    padding: var(--space-2) 0 var(--space-3);
  }
  .nav-toggle { display: inline-flex; }
  .rail-progress { display: none; }
  .rail-actions {
    flex-direction: row;
    flex-wrap: wrap;
  }
  .rail-actions .btn { flex: 1 1 160px; }

  .js .site-nav {
    display: grid;
    grid-template-rows: 0fr;
    transition: grid-template-rows 200ms ease;
  }
  .js .site-nav > .nav-list { overflow: hidden; }
  .js .site-nav[data-open="true"] { grid-template-rows: 1fr; }

  .nav-link { padding: 12px var(--space-2); }
  .nav-label { font-size: var(--text-base); }
}

@media (min-width: 1024px) {
  body { padding-left: calc(var(--space-8) * 3.5); }

  .site-header {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: calc(var(--space-8) * 3.5);
    border-right: var(--border-thin) solid var(--color-line);
  }
  .site-header::after {
    content: "";
    position: absolute;
    top: 0;
    right: 5px;
    bottom: 0;
    width: var(--border-thin);
    background-color: var(--color-line);
    opacity: 0.65;
    pointer-events: none;
  }

  .header-rail {
    display: flex;
    flex-direction: column;
    height: 100%;
    padding: var(--space-4) var(--space-3) var(--space-3);
    overflow-y: auto;
  }

  .site-nav { margin-top: var(--space-3); }
  .rail-foot { margin-top: auto; }
  .site-nav,
  .site-nav > .nav-list { overflow: visible; }
}

@media (max-width: 519px) {
  .footer-meta { margin-left: 0; }
  .to-top { right: var(--space-2); bottom: var(--space-2); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .media img,
  .btn,
  .nav-link,
  .nav-toggle-icon::before,
  .nav-toggle-icon::after { transition: none; }
  .media:hover img { transform: none; }
}