:root {
  --color-surface: #fafafa;
  --color-surface-alt: #f1f1f1;
  --color-surface-deep: #e4e5e5;
  --color-ink: #424a4d;
  --color-ink-soft: #646f72;
  --color-ink-muted: #798386;
  --color-line: #d9dadb;
  --color-primary: #257f97;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #dce9ec;
  --color-accent: #db3224;
  --color-accent-ink: #ffffff;
  --color-highlight: #f4d6d3;
  --color-focus: #da2516;
  --color-contrast-surface: #19282c;
  --color-contrast-ink: #e4e6e7;
  --color-contrast-line: #465255;
  --color-contrast-accent: #e46358;
  --overlay-scrim: linear-gradient(180deg, rgba(25, 40, 44, 0.35) 0%, rgba(25, 40, 44, 0.72) 55%, rgba(25, 40, 44, 0.92) 100%);
  --font-heading: ui-monospace, SFMono-Regular, Menlo, Consolas, "PingFang SC", monospace;
  --font-body: "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --text-xs: 9.7px;
  --text-sm: 13.0px;
  --text-base: 15px;
  --text-lg: 20.0px;
  --text-xl: 26.7px;
  --text-2xl: 35.5px;
  --text-3xl: 47.4px;
  --text-4xl: 63.1px;
  --text-display: clamp(41px, 8.4vw, 107px);
  --text-figure: clamp(34px, 6.0vw, 77px);
  --weight-heading: 785;
  --weight-body: 400;
  --leading-body: 1.78;
  --leading-heading: 1.16;
  --tracking-heading: 0.005em;
  --radius-sm: 243px;
  --radius-md: 503px;
  --radius-lg: 763px;
  --radius-pill: 999px;
  --border-thin: 1px;
  --border-thick: 2px;
  --shadow-1: 0 0 0 1px rgba(219, 50, 36, 0.35);
  --shadow-2: 0 0 28px rgba(219, 50, 36, 0.35);
  --space-1: 7px;
  --space-2: 14px;
  --space-3: 21px;
  --space-4: 28px;
  --space-6: 42px;
  --space-8: 56px;
  --container: 1160px;
  --measure: 66ch;
  --gutter: 21px;
  --section-y: 88px;
  --section-y-lg: 123px;
}

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background-color: 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);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

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

button { cursor: pointer; }

a { color: var(--color-primary); text-underline-offset: 3px; }

h1, h2, h3, h4, h5, h6 {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

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

ul, ol { margin: 0 0 var(--space-3); padding-left: 1.2em; }
li { margin-bottom: var(--space-1); }

hr { border: 0; border-top: var(--border-thin) dotted var(--color-line); margin: var(--space-6) 0; }

::selection {
  background-color: color-mix(in srgb, var(--color-primary) 32%, var(--color-surface));
  color: var(--color-ink);
}

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

.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;
}

.skip-link {
  position: absolute;
  left: var(--gutter);
  top: -120px;
  z-index: 200;
  display: inline-flex;
  align-items: center;
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid var(--color-contrast-accent);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  text-decoration: none;
  transition: top 0.16s ease;
}
.skip-link:focus { top: var(--space-2); }

/* ============================================================
   布局容器与栅格
   ============================================================ */
.container {
  width: 100%;
  max-width: calc(var(--container) + var(--gutter) * 2);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section { padding-block: var(--section-y); }
.section--lg { padding-block: var(--section-y-lg); }
.section--deep {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}
.section--deep h1,
.section--deep h2,
.section--deep h3 { color: var(--color-contrast-ink); }
.section--deep a { color: var(--color-contrast-accent); }

.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--gutter);
}
.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-9 { grid-column: span 9; }
.span-12 { grid-column: span 12; }

.divider-dotted {
  border: 0;
  border-top: var(--border-thin) dotted var(--color-line);
  margin: var(--space-6) 0;
}
.section--deep .divider-dotted { border-top-color: var(--color-contrast-line); }

/* ============================================================
   排版组件
   ============================================================ */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  margin: 0 0 var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}
.section--deep .eyebrow { color: var(--color-contrast-accent); }

.section-title {
  font-size: var(--text-2xl);
  margin: 0 0 var(--space-3);
}

.section-sub {
  font-size: var(--text-lg);
  color: var(--color-ink-soft);
  margin: 0 0 var(--space-4);
}
.section--deep .section-sub { color: var(--color-contrast-ink); }

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

.prose {
  max-width: var(--measure);
}
.prose h2 { font-size: var(--text-xl); margin: var(--space-6) 0 var(--space-2); }
.prose h3 { font-size: var(--text-lg); margin: var(--space-4) 0 var(--space-2); }
.prose p { margin-bottom: var(--space-3); }

.index-num {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}

.data-num {
  font-family: var(--font-mono);
  font-weight: var(--weight-heading);
  font-size: var(--text-2xl);
  letter-spacing: 0.02em;
  color: var(--color-primary);
}

.pullquote {
  position: relative;
  margin: var(--space-6) 0;
  padding: var(--space-2) 0 var(--space-2) var(--space-4);
  border-left: var(--border-thick) dotted var(--color-primary);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  line-height: 1.5;
  color: var(--color-ink);
}
.pullquote::before {
  content: "\201C";
  position: absolute;
  left: -2px;
  top: -0.42em;
  font-family: var(--font-heading);
  font-size: var(--text-2xl);
  line-height: 1;
  color: var(--color-primary);
}
.pullquote cite {
  display: block;
  margin-top: var(--space-2);
  font-family: var(--font-mono);
  font-style: normal;
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}
.section--deep .pullquote,
.section--deep .pullquote::before { color: var(--color-contrast-ink); }
.section--deep .pullquote { border-left-color: var(--color-contrast-accent); }

/* ============================================================
   头部
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 90;
  background-color: var(--color-surface);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.header-top {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.header-top__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  flex-wrap: wrap;
  min-height: 62px;
  padding-block: var(--space-2);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  color: var(--color-contrast-ink);
}

.brand__mark {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  flex: none;
  border-radius: var(--radius-md);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
  box-shadow: 0 0 0 1px color-mix(in srgb, var(--color-primary) 45%, #ffffff),
              0 0 18px color-mix(in srgb, var(--color-primary) 55%, transparent);
}

.brand__text { display: flex; flex-direction: column; line-height: 1.25; }

.brand__name {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
  letter-spacing: 0.1em;
  color: var(--color-contrast-ink);
}

.brand__line {
  font-size: var(--text-sm);
  color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent);
}

.statusbar {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.statusbar__item {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 6px var(--space-3) 6px var(--space-2);
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid var(--color-contrast-line);
  background-color: color-mix(in srgb, var(--color-contrast-line) 26%, transparent);
  white-space: nowrap;
}

.statusbar__key {
  font-size: var(--text-sm);
  color: color-mix(in srgb, var(--color-contrast-ink) 66%, transparent);
}

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

.lamp {
  width: 7px;
  height: 7px;
  flex: none;
  border-radius: var(--radius-pill);
  background-color: var(--color-contrast-accent);
  box-shadow: 0 0 8px var(--color-contrast-accent);
}

.lamp--live { animation: lamp-pulse 2.6s ease-in-out infinite; }

@keyframes lamp-pulse {
  0%, 100% { opacity: 1; box-shadow: 0 0 8px var(--color-contrast-accent); }
  50% { opacity: 0.45; box-shadow: 0 0 2px var(--color-contrast-accent); }
}

.header-nav { background-color: var(--color-surface); }

.header-nav__inner {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
  min-height: 58px;
  padding-block: var(--space-2);
}

.site-nav { flex: 1 1 auto; min-width: 0; }

.site-nav__list {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  flex-wrap: wrap;
  margin: 0;
  padding: 0;
  list-style: none;
}
.site-nav__list > li { margin: 0; }

.nav-pill {
  display: inline-flex;
  align-items: baseline;
  gap: var(--space-1);
  padding: 8px var(--space-3);
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface-alt);
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  text-decoration: none;
  transition: background-color 0.16s ease, border-color 0.16s ease,
              color 0.16s ease, transform 0.16s ease;
}

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

.nav-pill:hover {
  color: var(--color-primary);
  border-color: color-mix(in srgb, var(--color-primary) 52%, var(--color-line));
  background-color: var(--color-primary-soft);
  transform: translateY(-1px);
}

.nav-pill:hover .nav-pill__idx { color: var(--color-primary); }

.nav-pill[aria-current="page"] {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background-color: var(--color-surface);
  box-shadow: 0 0 0 1px var(--color-primary),
              0 0 18px color-mix(in srgb, var(--color-primary) 28%, transparent);
}
.nav-pill[aria-current="page"] .nav-pill__idx { color: var(--color-primary); }

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-2);
  padding: 8px var(--space-3);
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface-alt);
  color: var(--color-ink);
  font-size: var(--text-sm);
}

.nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  gap: 3px;
  width: 14px;
}
.nav-toggle__bars i {
  display: block;
  height: 2px;
  border-radius: var(--radius-pill);
  background-color: currentColor;
}

.nav-toggle[aria-expanded="true"] {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background-color: var(--color-primary-soft);
}

.progress-rail {
  height: 3px;
  background-color: var(--color-surface-deep);
  overflow: hidden;
}

.progress-rail__bar {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background-image: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  box-shadow: 0 0 12px color-mix(in srgb, var(--color-accent) 60%, transparent);
}

/* ============================================================
   按钮、胶囊、标签
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 10px var(--space-4);
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid var(--color-primary);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  text-decoration: none;
  transition: transform 0.16s ease, box-shadow 0.16s ease, background-color 0.16s ease;
}
.btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 0 0 1px color-mix(in srgb, var(--color-primary) 60%, transparent),
              0 0 20px color-mix(in srgb, var(--color-primary) 40%, transparent);
}

.btn--accent {
  border-color: var(--color-accent);
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.btn--accent:hover {
  box-shadow: 0 0 0 1px color-mix(in srgb, var(--color-accent) 60%, transparent),
              0 0 20px color-mix(in srgb, var(--color-accent) 42%, transparent);
}

.btn--ghost {
  background-color: transparent;
  border-color: var(--color-line);
  color: var(--color-ink);
}
.btn--ghost:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  box-shadow: none;
  background-color: var(--color-primary-soft);
}

.section--deep .btn--ghost {
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
}
.section--deep .btn--ghost:hover {
  border-color: var(--color-contrast-accent);
  color: var(--color-contrast-accent);
  background-color: color-mix(in srgb, var(--color-contrast-accent) 14%, transparent);
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 7px var(--space-3);
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface-alt);
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  line-height: 1.25;
  text-decoration: none;
  transition: color 0.16s ease, border-color 0.16s ease, background-color 0.16s ease;
}

button.pill { font-family: inherit; }

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

.pill--on,
.pill[aria-pressed="true"],
.pill[aria-selected="true"] {
  border-color: var(--color-primary);
  background-color: var(--color-primary-soft);
  color: var(--color-primary);
  box-shadow: 0 0 0 1px color-mix(in srgb, var(--color-primary) 45%, transparent);
}

.pill--accent {
  border-color: var(--color-accent);
  background-color: var(--color-highlight);
  color: color-mix(in srgb, var(--color-accent) 88%, var(--color-ink));
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 4px var(--space-2);
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}

.tag--primary {
  border-color: color-mix(in srgb, var(--color-primary) 50%, var(--color-line));
  background-color: var(--color-primary-soft);
  color: color-mix(in srgb, var(--color-primary) 90%, var(--color-ink));
}

.tag--accent {
  border-color: color-mix(in srgb, var(--color-accent) 50%, var(--color-line));
  background-color: var(--color-highlight);
  color: color-mix(in srgb, var(--color-accent) 88%, var(--color-ink));
}

/* ============================================================
   面板、卡片、状态条
   ============================================================ */
.panel {
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface-alt);
  padding: var(--space-4);
}

.panel--plain { background-color: var(--color-surface); }
.panel--deep {
  border-color: var(--color-contrast-line);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}
.panel--deep h3 { color: var(--color-contrast-ink); }

.card {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface);
  padding: var(--space-3);
}

.card__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2);
}

.card__title {
  font-size: var(--text-lg);
  margin: 0;
}

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

.card__foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  padding-top: var(--space-2);
  border-top: var(--border-thin) dotted var(--color-line);
}

.statusline {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface-alt);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  color: var(--color-ink-soft);
}

.statusline__track {
  position: relative;
  flex: 1 1 auto;
  min-width: 60px;
  height: 6px;
  border-radius: var(--radius-pill);
  background-color: var(--color-surface-deep);
  overflow: hidden;
}
.statusline__fill {
  display: block;
  height: 100%;
  border-radius: var(--radius-pill);
  background-color: var(--color-primary);
}
.statusline--accent .statusline__fill { background-color: var(--color-accent); }

/* ============================================================
   面包屑
   ============================================================ */
.breadcrumbs {
  padding-block: var(--space-3);
  border-bottom: var(--border-thin) dotted var(--color-line);
}
.breadcrumbs__list {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  flex-wrap: wrap;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}
.breadcrumbs__list > li { margin: 0; }
.breadcrumbs__list > li + li::before {
  content: "/";
  margin-right: var(--space-1);
  color: var(--color-line);
}
.breadcrumbs__list a { color: var(--color-ink-soft); text-decoration: none; }
.breadcrumbs__list a:hover { color: var(--color-primary); }
.breadcrumbs__list [aria-current="page"] { color: var(--color-ink); }

/* ============================================================
   图录式图片容器
   ============================================================ */
.figure {
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.figure__frame {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 16 / 10;
  overflow: hidden;
  border-radius: var(--radius-md);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface-alt);
  background-image: linear-gradient(
    135deg,
    color-mix(in srgb, var(--color-primary) 22%, var(--color-surface-alt)) 0%,
    color-mix(in srgb, var(--color-contrast-surface) 82%, var(--color-primary)) 72%
  );
}

.figure__frame--wide { aspect-ratio: 21 / 9; border-radius: var(--radius-sm); }
.figure__frame--portrait { aspect-ratio: 3 / 4; border-radius: var(--radius-md); }
.figure__frame--square { aspect-ratio: 1 / 1; border-radius: var(--radius-lg); }

.figure__frame > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

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

.figure__overlay {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: var(--space-3);
  color: var(--color-contrast-ink);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  line-height: var(--leading-heading);
}

.figure__label {
  position: absolute;
  top: var(--space-2);
  left: var(--space-2);
  display: inline-flex;
  align-items: center;
  padding: 4px var(--space-2);
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-contrast-ink) 34%, transparent);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
}

.figure__caption {
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
  line-height: 1.55;
}

.figure-gallery {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--gutter);
}

/* ============================================================
   页内目录高亮
   ============================================================ */
[data-toc] a[data-active] {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background-color: var(--color-primary-soft);
}

/* ============================================================
   滚动显现
   ============================================================ */
.js-on [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
.js-on [data-reveal][data-revealed] {
  opacity: 1;
  transform: none;
}

/* ============================================================
   页脚
   ============================================================ */
.site-footer {
  margin-top: var(--space-8);
  border-top: var(--border-thin) dotted var(--color-contrast-line);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.footer-inner {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-2) var(--space-4);
  padding-block: var(--space-6);
}

.footer-brand {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  flex-wrap: wrap;
  margin: 0;
}

.footer-brand__name {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
  letter-spacing: 0.1em;
  color: var(--color-contrast-ink);
}

.footer-brand__meta {
  font-size: var(--text-sm);
  color: color-mix(in srgb, var(--color-contrast-ink) 58%, transparent);
}

.footer-links {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
}

.footer-links a {
  padding: 6px var(--space-3);
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid var(--color-contrast-line);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  text-decoration: none;
  transition: border-color 0.16s ease, color 0.16s ease, background-color 0.16s ease;
}
.footer-links a:hover {
  border-color: var(--color-contrast-accent);
  color: var(--color-contrast-accent);
  background-color: color-mix(in srgb, var(--color-contrast-accent) 14%, transparent);
}

.footer-contact {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
  margin: 0 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.04em;
  color: color-mix(in srgb, var(--color-contrast-ink) 78%, transparent);
}

.footer-icp,
.footer-year { color: color-mix(in srgb, var(--color-contrast-ink) 60%, transparent); }

.to-top {
  position: fixed;
  right: var(--space-4);
  bottom: var(--space-4);
  z-index: 95;
  padding: 9px var(--space-3);
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid var(--color-contrast-line);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity 0.2s ease, transform 0.2s ease, visibility 0.2s ease;
}
.to-top[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: none;
}
.to-top:hover { border-color: var(--color-contrast-accent); color: var(--color-contrast-accent); }

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 1024px) {
  .span-3, .span-4, .span-5 { grid-column: span 6; }
  .span-7, .span-8, .span-9 { grid-column: span 12; }
}

@media (max-width: 900px) {
  .header-nav__inner { align-items: flex-start; }
  .nav-toggle { display: inline-flex; }

  .site-nav {
    display: none;
    flex: 1 0 100%;
    width: 100%;
  }
  .site-nav[data-open] { display: block; }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 6px;
    padding-bottom: var(--space-2);
  }
  .nav-pill {
    justify-content: space-between;
    border-radius: var(--radius-md);
    padding: 10px var(--space-3);
  }

  .footer-inner { flex-direction: column; align-items: flex-start; gap: var(--space-3); }
  .footer-contact { margin-left: 0; }
}

@media (max-width: 720px) {
  .grid-12 { grid-template-columns: minmax(0, 1fr); gap: var(--space-3); }
  .span-3, .span-4, .span-5, .span-6, .span-7, .span-8, .span-9, .span-12 {
    grid-column: span 1;
  }

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

  .header-top__inner { min-height: 0; }
  .statusbar { width: 100%; }
  .statusbar__item { flex: 1 1 auto; justify-content: center; }
  .statusbar__key { display: none; }

  .footer-links { gap: var(--space-2); }
  .to-top { right: var(--space-3); bottom: var(--space-3); }
}

@media (max-width: 420px) {
  .brand__line { display: none; }
  .statusbar__val { font-size: var(--text-xs); }
}

/* ============================================================
   可访问性偏好
   ============================================================ */
@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;
  }

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

  .progress-rail__bar { transition: none; }
}