:root {
  --color-surface: #f8f8f8;
  --color-surface-alt: #efeff0;
  --color-surface-deep: #e3e3e4;
  --color-ink: #45474f;
  --color-ink-soft: #696c77;
  --color-ink-muted: #797c86;
  --color-line: #d8d8da;
  --color-primary: #5869a7;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #e2e4ed;
  --color-accent: #d42b47;
  --color-accent-ink: #ffffff;
  --color-highlight: #f2d3d8;
  --color-focus: #dc1e3d;
  --color-contrast-surface: #131419;
  --color-contrast-ink: #e4e5e7;
  --color-contrast-line: #414246;
  --color-contrast-accent: #db4d64;
  --overlay-scrim: linear-gradient(180deg, rgba(19, 20, 25, 0.35) 0%, rgba(19, 20, 25, 0.72) 55%, rgba(19, 20, 25, 0.92) 100%);
  --font-heading: "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --text-xs: 11.4px;
  --text-sm: 13.7px;
  --text-base: 15px;
  --text-lg: 18.0px;
  --text-xl: 21.6px;
  --text-2xl: 25.9px;
  --text-3xl: 31.1px;
  --text-4xl: 37.3px;
  --text-display: clamp(34px, 4.8vw, 61px);
  --text-figure: clamp(28px, 3.4vw, 44px);
  --weight-heading: 700;
  --weight-body: 400;
  --leading-body: 1.64;
  --leading-heading: 1.25;
  --tracking-heading: -0.01em;
  --radius-sm: 4px;
  --radius-md: 5px;
  --radius-lg: 6px;
  --radius-pill: 6px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: 0 1px 0 rgba(69, 71, 79, 0.12);
  --shadow-2: 0 2px 0 rgba(69, 71, 79, 0.18);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1160px;
  --measure: 74ch;
  --gutter: 16px;
  --section-y: 68px;
  --section-y-lg: 95px;
}

/* ============ reset ============ */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-padding-top: 84px;
}

body {
  margin: 0;
  background: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

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

button { font-family: inherit; }

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

/* ============ 中文排版 ============ */
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); }
p:last-child { margin-bottom: 0; }

ul, ol { margin: 0 0 var(--space-2); padding-left: 1.15em; }
li { margin-bottom: 4px; }
li:last-child { margin-bottom: 0; }

a { color: var(--color-primary); text-decoration: none; }

b, strong { font-weight: var(--weight-heading); }

code, kbd, samp { font-family: var(--font-mono); font-size: 0.94em; }

hr { border: 0; border-top: 1px solid var(--color-line); margin: var(--space-3) 0; }

/* 链接下划线由左向右展开 */
.link-underline {
  background-image: linear-gradient(currentColor, currentColor);
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 0 1px;
  transition: background-size 160ms ease-out, color 160ms ease-out;
}
.link-underline:hover,
.link-underline:focus-visible { background-size: 100% 1px; }

/* ============ 焦点 ============ */
:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 1px;
}
.site-header :focus-visible,
.band-dark :focus-visible,
.site-footer :focus-visible { outline-color: var(--color-contrast-accent); }
.site-footer :focus-visible { outline-color: var(--color-focus); }

/* ============ 布局工具 ============ */
.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.prose { max-width: var(--measure); }
.prose p { margin: 0 0 var(--space-2); }

.section { padding: var(--section-y) 0; }
.section-lg { padding: var(--section-y-lg) 0; }
.section-tight { padding: var(--space-3) 0; }

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-1) var(--space-3);
  padding-bottom: var(--space-1);
  margin-bottom: var(--space-3);
  border-bottom: 2px solid var(--color-ink);
}
.section-head h2,
.section-head h3 { margin: 0; }

.grid-2,
.grid-3,
.grid-4 {
  display: grid;
  gap: var(--space-3);
}
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); }
.grid-4 { grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); }

.grid12 {
  display: grid;
  gap: var(--gutter);
  grid-template-columns: repeat(12, minmax(0, 1fr));
}
.span-3 { grid-column: span 3; }
.span-4 { grid-column: span 4; }
.span-5 { grid-column: span 5; }
.span-6 { grid-column: span 6; }
.span-7 { grid-column: span 7; }
.span-8 { grid-column: span 8; }
.span-12 { grid-column: span 12; }

.rule-double {
  border: 0;
  border-top: 1px solid var(--color-line);
  border-bottom: 1px solid var(--color-line);
  height: 3px;
  margin: var(--space-3) 0;
}
.rule-thick {
  border: 0;
  border-top: 2px solid var(--color-ink);
  margin: var(--space-3) 0 var(--space-2);
}

.head-slab {
  display: inline-block;
  background: var(--color-surface-deep);
  color: var(--color-ink);
  padding: var(--space-1) var(--space-3);
  clip-path: polygon(0 0, calc(100% - 14px) 0, 100% 14px, 100% 100%, 0 100%);
}

/* ============ 文字组件 ============ */
.mono,
.num,
.metric-value,
.metric-unit,
.nav-idx,
.nav-caption,
.rail-status,
.rail-links a,
.breadcrumb,
.footer-col-title,
.footer-legal-line,
.footer-policy,
.footer-spec b,
.fc-key,
.figure-caption,
.tag,
.panel-head,
.data-table .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum" 1;
}

.display-title {
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  margin: 0;
}

.lede {
  font-size: var(--text-lg);
  color: var(--color-ink-soft);
  max-width: var(--measure);
  margin: 0 0 var(--space-3);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}
.eyebrow::before {
  content: "";
  width: 18px;
  height: 2px;
  background: var(--color-primary);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* ============ 标签 ============ */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  line-height: 1.4;
  padding: 3px 7px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-surface-alt);
  color: var(--color-ink-soft);
  white-space: nowrap;
}
.tag-primary {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
}
.tag-accent {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.tag-highlight {
  background: var(--color-highlight);
  border-color: color-mix(in srgb, var(--color-accent) 35%, transparent);
  color: color-mix(in srgb, var(--color-accent) 78%, var(--color-ink));
}

/* ============ 按钮 ============ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 10px 18px;
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  letter-spacing: 0.02em;
  border: 1px solid var(--color-primary);
  border-radius: var(--radius-sm);
  background: var(--color-primary);
  color: var(--color-primary-ink);
  cursor: pointer;
  transition: background-color 150ms ease-out, border-color 150ms ease-out, color 150ms ease-out, transform 150ms ease-out;
}
.btn:hover {
  background: color-mix(in srgb, var(--color-primary) 78%, var(--color-contrast-surface));
  border-color: color-mix(in srgb, var(--color-primary) 78%, var(--color-contrast-surface));
  color: var(--color-primary-ink);
}
.btn:active { transform: translateY(1px); }

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

.btn-accent {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.btn-accent:hover {
  background: color-mix(in srgb, var(--color-accent) 80%, var(--color-contrast-surface));
  border-color: color-mix(in srgb, var(--color-accent) 80%, var(--color-contrast-surface));
  color: var(--color-accent-ink);
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-3);
}

/* ============ 面包屑 ============ */
.breadcrumb {
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
  padding: var(--space-2) 0 0;
}
.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.breadcrumb li { margin: 0; }
.breadcrumb li + li::before {
  content: "/";
  margin-right: 6px;
  color: var(--color-line);
}
.breadcrumb a { color: var(--color-ink-soft); }
.breadcrumb a:hover { color: var(--color-primary); }
.breadcrumb [aria-current="page"] { color: var(--color-ink); }

/* ============ 指标配对 ============ */
.metric-pair {
  display: grid;
  grid-template-columns: minmax(0, 4fr) minmax(0, 3fr);
  gap: var(--space-1) var(--space-3);
  align-items: start;
  padding: var(--space-3) 0;
  border-top: 1px solid var(--color-line);
}

.metric-toggle {
  justify-self: start;
  width: 100%;
  text-align: left;
  font: inherit;
  color: inherit;
  cursor: pointer;
  background: transparent;
  border: 1px solid transparent;
  border-left: 3px solid var(--color-primary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: var(--space-1) var(--space-2) var(--space-1) var(--space-2);
  transition: background-color 150ms ease-out, border-color 150ms ease-out;
}
.metric-toggle:hover,
.metric-toggle[aria-expanded="true"] {
  background: var(--color-primary-soft);
  border-color: color-mix(in srgb, var(--color-primary) 45%, var(--color-line));
  border-left-color: var(--color-primary);
}

.metric-value {
  display: block;
  font-size: var(--text-figure);
  font-weight: var(--weight-heading);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--color-ink);
}
.metric-unit {
  display: inline-block;
  font-size: var(--text-sm);
  font-weight: var(--weight-body);
  letter-spacing: 0.04em;
  margin-left: 6px;
  color: var(--color-ink-muted);
  vertical-align: 0.28em;
}
.metric-label {
  display: block;
  margin-top: var(--space-1);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}

.metric-note {
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-ink-muted);
  border-left: 1px solid var(--color-line);
  padding-left: var(--space-2);
}
.metric-note[hidden] { display: none; }

/* ============ 深色带 ============ */
.band-dark {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  padding: var(--section-y) 0;
}
.band-dark h1,
.band-dark h2,
.band-dark h3,
.band-dark h4,
.band-dark h5 { color: var(--color-contrast-ink); }
.band-dark .lede,
.band-dark p { color: color-mix(in srgb, var(--color-contrast-ink) 78%, var(--color-contrast-surface)); }
.band-dark .metric-value { color: var(--color-contrast-ink); }
.band-dark .metric-label,
.band-dark .metric-unit { color: color-mix(in srgb, var(--color-contrast-ink) 66%, var(--color-contrast-surface)); }
.band-dark .metric-pair { border-top-color: var(--color-contrast-line); }
.band-dark .metric-note {
  color: color-mix(in srgb, var(--color-contrast-ink) 68%, var(--color-contrast-surface));
  border-left-color: var(--color-contrast-line);
}
.band-dark .metric-toggle:hover,
.band-dark .metric-toggle[aria-expanded="true"] {
  background: color-mix(in srgb, var(--color-primary) 30%, transparent);
  border-color: var(--color-primary);
  border-left-color: var(--color-contrast-accent);
}
.band-dark .rule-double,
.band-dark .rule-thick { border-color: var(--color-contrast-line); }
.band-dark .section-head { border-bottom-color: var(--color-contrast-ink); }
.band-dark .eyebrow { color: color-mix(in srgb, var(--color-contrast-ink) 62%, var(--color-contrast-surface)); }
.band-dark a { color: color-mix(in srgb, var(--color-primary) 45%, var(--color-contrast-ink)); }
.band-dark .tag {
  background: transparent;
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
}
.band-dark .tag-accent {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}

/* ============ 图表 ============ */
.chart {
  display: block;
  width: 100%;
  height: auto;
  overflow: visible;
}
.chart .bar { fill: var(--color-primary); }
.chart .bar-alt { fill: color-mix(in srgb, var(--color-primary) 38%, var(--color-surface)); }
.chart .bar-accent { fill: var(--color-accent); }
.chart .line { fill: none; stroke: var(--color-primary); stroke-width: 1.5; }
.chart .line-accent { fill: none; stroke: var(--color-accent); stroke-width: 1.5; }
.chart .grid-line { stroke: var(--color-line); stroke-width: 1; }
.band-dark .chart .bar-alt { fill: color-mix(in srgb, var(--color-contrast-ink) 22%, var(--color-contrast-surface)); }
.band-dark .chart .grid-line { stroke: var(--color-contrast-line); }
.band-dark .chart .line { stroke: color-mix(in srgb, var(--color-primary) 50%, var(--color-contrast-ink)); }
.band-dark .chart .bar-accent { fill: var(--color-contrast-accent); }

/* ============ 表格 ============ */
.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--text-sm);
  background: var(--color-surface);
}
.data-table caption {
  caption-side: top;
  text-align: left;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
  padding: 0 0 var(--space-1);
}
.data-table thead th {
  background: var(--color-surface-deep);
  color: var(--color-ink);
  font-weight: var(--weight-heading);
  text-align: left;
  padding: 9px 12px;
  border-bottom: 1px solid var(--color-line);
  border-top: 2px solid var(--color-ink);
  white-space: nowrap;
}
.data-table td {
  padding: 9px 12px;
  border-bottom: 1px solid var(--color-line);
  vertical-align: top;
}
.data-table tbody tr:nth-child(even) { background: var(--color-surface-alt); }
.data-table tbody tr:hover { background: var(--color-primary-soft); }
.data-table .num { text-align: right; }
.data-table tbody tr[aria-selected="true"] { background: var(--color-primary-soft); }
.data-table tbody tr[aria-selected="true"] td:first-child { box-shadow: inset 3px 0 0 var(--color-primary); }

/* ============ 面板 ============ */
.panel {
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  overflow: hidden;
}
.panel-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-1) var(--space-2);
  padding: 10px 14px;
  background: var(--color-surface-deep);
  border-bottom: 1px solid var(--color-line);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-ink-soft);
}
.panel-body { padding: var(--space-3); }
.band-dark .panel {
  background: color-mix(in srgb, var(--color-contrast-ink) 6%, var(--color-contrast-surface));
  border-color: var(--color-contrast-line);
}
.band-dark .panel-head {
  background: color-mix(in srgb, var(--color-contrast-ink) 10%, var(--color-contrast-surface));
  border-bottom-color: var(--color-contrast-line);
  color: color-mix(in srgb, var(--color-contrast-ink) 72%, var(--color-contrast-surface));
}

/* ============ 图片容器 ============ */
.figure-frame {
  position: relative;
  display: block;
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-contrast-surface);
}
.figure-frame img,
.figure-frame .figure-media {
  display: block;
  width: 100%;
  height: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  filter: saturate(0.92) contrast(1.08) brightness(0.86);
}
.figure-frame--wide img,
.figure-frame--wide .figure-media { aspect-ratio: 21 / 9; }
.figure-frame--tall img,
.figure-frame--tall .figure-media { aspect-ratio: 4 / 5; }

.figure-caption {
  position: absolute;
  left: 0;
  bottom: 0;
  z-index: 2;
  margin: 0;
  padding: 5px 10px;
  font-size: var(--text-xs);
  letter-spacing: 0.04em;
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-top-right-radius: var(--radius-sm);
}
.figure-frame--overlay::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  background: var(--overlay-scrim);
}
.figure-frame--overlay .figure-caption {
  background: transparent;
  color: var(--color-contrast-ink);
}
.figure-frame figcaption { margin: 0; }

/* ============ 跳至主要内容 ============ */
.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 200;
  padding: 9px 16px;
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  color: var(--color-accent-ink);
  background: var(--color-accent);
  border-radius: var(--radius-sm);
  transform: translateY(-180%);
  transition: transform 150ms ease-out;
}
.skip-link:focus {
  transform: translateY(0);
  color: var(--color-accent-ink);
}

/* ============ 头部 ============ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  padding: 10px var(--space-2);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-bottom: 1px solid var(--color-contrast-line);
}

.rail-brand { flex: 1 1 auto; min-width: 0; }

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
  color: var(--color-contrast-ink);
  text-decoration: none;
}
.brand:hover { color: var(--color-contrast-ink); }

.brand-mark {
  flex: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 4px 7px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--weight-heading);
  letter-spacing: 0.16em;
  background: var(--color-primary);
  color: var(--color-primary-ink);
  clip-path: polygon(0 0, calc(100% - 6px) 0, 100% 6px, 100% 100%, 0 100%);
}

.brand-text {
  display: flex;
  flex-direction: column;
  min-width: 0;
}
.brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: 1.2;
  letter-spacing: var(--tracking-heading);
}
.brand-sub {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  line-height: 1.4;
  color: color-mix(in srgb, var(--color-contrast-ink) 66%, var(--color-contrast-surface));
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* 移动端抽屉按钮 */
.nav-toggle {
  flex: none;
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 8px 11px;
  background: transparent;
  border: 1px solid var(--color-contrast-line);
  border-radius: var(--radius-sm);
  color: var(--color-contrast-ink);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  cursor: pointer;
  transition: background-color 150ms ease-out, border-color 150ms ease-out, color 150ms ease-out;
}
.nav-toggle:hover { border-color: var(--color-primary); }
.nav-toggle[aria-expanded="true"] {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.nav-toggle-bars {
  display: inline-block;
  width: 16px;
  height: 11px;
  background-image:
    linear-gradient(currentColor, currentColor),
    linear-gradient(currentColor, currentColor),
    linear-gradient(currentColor, currentColor);
  background-size: 100% 1px;
  background-position: 0 0, 0 5px, 0 10px;
  background-repeat: no-repeat;
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars {
  background-position: 0 5px, 0 -40px, 0 5px;
}

/* 导航 */
.site-nav {
  flex-basis: 100%;
  display: none;
  padding: 12px 0 4px;
}
.site-nav[data-open] { display: block; }

.nav-caption {
  margin: 0 0 var(--space-1);
  padding-bottom: 6px;
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: color-mix(in srgb, var(--color-contrast-ink) 56%, var(--color-contrast-surface));
  border-bottom: 1px solid var(--color-contrast-line);
}

.nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-list li { margin: 0; }
.nav-list a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 10px 10px 10px 12px;
  font-size: var(--text-base);
  color: color-mix(in srgb, var(--color-contrast-ink) 84%, var(--color-contrast-surface));
  border-left: 3px solid transparent;
  border-bottom: 1px solid color-mix(in srgb, var(--color-contrast-line) 70%, transparent);
  transition: color 150ms ease-out, border-color 150ms ease-out, background-color 150ms ease-out;
}
.nav-list a:hover {
  color: var(--color-contrast-ink);
  border-left-color: var(--color-primary);
  background: color-mix(in srgb, var(--color-contrast-ink) 8%, transparent);
}
.nav-list a[aria-current="page"] {
  color: color-mix(in srgb, var(--color-primary) 42%, var(--color-contrast-ink));
  border-left-color: var(--color-contrast-accent);
  background: color-mix(in srgb, var(--color-primary) 24%, transparent);
}
.nav-idx {
  flex: none;
  min-width: 22px;
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  opacity: 0.62;
}
.nav-label { min-width: 0; }

.rail-meta {
  margin-top: var(--space-2);
  padding-top: var(--space-2);
  border-top: 1px solid var(--color-contrast-line);
}
.rail-status {
  margin: 0 0 var(--space-2);
  font-size: var(--text-xs);
  line-height: 1.6;
  letter-spacing: 0.02em;
  color: color-mix(in srgb, var(--color-contrast-ink) 68%, var(--color-contrast-surface));
}
.rail-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.rail-links li { margin: 0; }
.rail-links a {
  display: block;
  padding: 7px 9px;
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: color-mix(in srgb, var(--color-contrast-ink) 74%, var(--color-contrast-surface));
  border: 1px solid var(--color-contrast-line);
  border-radius: var(--radius-sm);
  transition: border-color 150ms ease-out, color 150ms ease-out, background-color 150ms ease-out;
}
.rail-links a:hover {
  color: var(--color-contrast-ink);
  border-color: var(--color-contrast-accent);
  background: color-mix(in srgb, var(--color-contrast-ink) 8%, transparent);
}

/* ============ 页脚 ============ */
.site-footer {
  position: relative;
  background: var(--color-surface);
  color: var(--color-ink);
  border-top: 1px solid var(--color-line);
  padding: var(--space-6) 0 var(--space-4);
}
.site-footer::before {
  content: "";
  position: absolute;
  top: 4px;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--color-line);
}

.footer-inner {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--gutter);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-4) var(--space-3);
}

.footer-brand-name {
  margin: 0 0 4px;
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}
.footer-brand-sub {
  margin: 0 0 var(--space-1);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}
.footer-brand-meta {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.04em;
  color: var(--color-ink-muted);
}

.footer-col-title {
  margin: 0 0 var(--space-2);
  padding-bottom: 6px;
  font-size: var(--text-xs);
  font-weight: var(--weight-body);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
  border-bottom: 1px solid var(--color-line);
}

.footer-col ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 7px;
}
.footer-col li { margin: 0; }
.footer-col a {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  background-image: linear-gradient(currentColor, currentColor);
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 0 1px;
  transition: background-size 160ms ease-out, color 160ms ease-out;
}
.footer-col a:hover,
.footer-col a:focus-visible {
  color: var(--color-primary);
  background-size: 100% 1px;
}

.footer-spec li {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2);
  padding-bottom: 6px;
  border-bottom: 1px solid var(--color-line);
  font-size: var(--text-sm);
}
.footer-spec span { color: var(--color-ink-muted); }
.footer-spec b {
  font-weight: var(--weight-heading);
  color: var(--color-ink);
  letter-spacing: 0.02em;
}

.footer-contact li {
  display: grid;
  gap: 2px;
}
.fc-key {
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}
.fc-val {
  font-size: var(--text-sm);
  color: var(--color-ink);
  word-break: break-word;
}

.footer-legal {
  width: 100%;
  max-width: var(--container);
  margin: var(--space-6) auto 0;
  padding: var(--space-2) var(--gutter) 0;
  border-top: 1px solid var(--color-line);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-1) var(--space-4);
}
.footer-legal-line {
  margin: 0;
  font-size: var(--text-xs);
  letter-spacing: 0.02em;
  color: var(--color-ink-muted);
}
.footer-policy {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  font-size: var(--text-xs);
}
.footer-policy li { margin: 0; }
.footer-policy a {
  color: var(--color-ink-soft);
  background-image: linear-gradient(currentColor, currentColor);
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 0 1px;
  transition: background-size 160ms ease-out, color 160ms ease-out;
}
.footer-policy a:hover,
.footer-policy a:focus-visible {
  color: var(--color-accent);
  background-size: 100% 1px;
}

/* ============ 响应式 ============ */
@media (max-width: 640px) {
  .metric-pair { grid-template-columns: minmax(0, 1fr); }
  .metric-note {
    border-left: 0;
    border-top: 1px solid var(--color-line);
    padding-left: 0;
    padding-top: var(--space-1);
  }
  .band-dark .metric-note {
    border-top-color: var(--color-contrast-line);
  }
  .brand-sub { display: none; }
  .footer-legal { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 1023px) {
  .grid12 > .span-3,
  .grid12 > .span-4,
  .grid12 > .span-5,
  .grid12 > .span-6,
  .grid12 > .span-7,
  .grid12 > .span-8 { grid-column: 1 / -1; }
}

@media (min-width: 700px) {
  .footer-inner { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (min-width: 1024px) {
  html { scroll-padding-top: 24px; }

  body { padding-left: 220px; }

  .site-header {
    position: fixed;
    inset: 0 auto 0 0;
    width: 220px;
    flex-direction: column;
    flex-wrap: nowrap;
    align-items: stretch;
    gap: 0;
    padding: var(--space-3) var(--space-2) var(--space-2);
    border-bottom: 0;
    border-right: 1px solid var(--color-contrast-line);
    overflow-y: auto;
  }

  .rail-brand { flex: none; width: 100%; }

  .nav-toggle { display: none; }

  .site-nav,
  .site-nav[data-open] {
    display: flex;
    flex-direction: column;
    flex: 1 1 auto;
    min-height: 0;
    padding: 0;
    margin-top: var(--space-3);
  }

  .nav-caption { letter-spacing: 0.18em; }

  .rail-meta { margin-top: auto; }

  .footer-inner { grid-template-columns: 1.4fr 1fr 1fr 1.3fr; gap: var(--space-4); }
  .footer-legal { margin-top: var(--space-8); }
}

/* ============ 减少动态 ============ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition-duration: 0.001ms !important;
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
  }
  .btn:active { transform: none; }
  .skip-link { transition: none; }
}