:root {
  --color-surface: #fcfcfc;
  --color-surface-alt: #f2f2f2;
  --color-surface-deep: #e5e4e4;
  --color-ink: #3a3331;
  --color-ink-soft: #6a5f5d;
  --color-ink-muted: #847876;
  --color-line: #d9d8d7;
  --color-primary: #c0543f;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #f4e4e2;
  --color-accent: #0c8198;
  --color-accent-ink: #ffffff;
  --color-highlight: #d1e6ea;
  --color-focus: #037e96;
  --color-contrast-surface: #281c19;
  --color-contrast-ink: #e7e5e4;
  --color-contrast-line: #524846;
  --color-contrast-accent: #12caed;
  --overlay-scrim: linear-gradient(180deg, rgba(40, 28, 25, 0.35) 0%, rgba(40, 28, 25, 0.72) 55%, rgba(40, 28, 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: 12.2px;
  --text-sm: 15.2px;
  --text-base: 17px;
  --text-lg: 21.2px;
  --text-xl: 26.6px;
  --text-2xl: 33.2px;
  --text-3xl: 41.5px;
  --text-4xl: 51.9px;
  --text-display: clamp(51px, 10.4vw, 133px);
  --text-figure: clamp(42px, 7.5vw, 96px);
  --weight-heading: 740;
  --weight-body: 400;
  --leading-body: 1.69;
  --leading-heading: 1.21;
  --tracking-heading: -0.004em;
  --radius-sm: 3px;
  --radius-md: 4px;
  --radius-lg: 6px;
  --radius-pill: 6px;
  --border-thin: 1px;
  --border-thick: 2px;
  --shadow-1: none;
  --shadow-2: none;
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1200px;
  --measure: 74ch;
  --gutter: 24px;
  --section-y: 75px;
  --section-y-lg: 105px;
}

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 140px;
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-weight: var(--weight-body);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink);
  background-color: var(--color-surface);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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);
  text-wrap: balance;
}

p { margin: 0 0 var(--space-2); }
p:last-child { margin-bottom: 0; }

ul, ol { margin: 0; padding: 0; }

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

button { font: inherit; color: inherit; }

a {
  color: var(--color-accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
a:hover { color: color-mix(in srgb, var(--color-accent) 76%, var(--color-ink)); }

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

hr { border: 0; }

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

:where(a, button, summary, [tabindex]):focus-visible {
  outline: var(--border-thick) solid var(--color-focus);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* 数字统一等宽，仪表感 */
.num,
.readout__value,
.stat-value,
.mono { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }

/* ============ 布局骨架 ============ */
.container {
  width: min(calc(100% - (var(--gutter) * 2)), var(--container));
  margin-inline: auto;
}

.grid {
  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; }

.split {
  display: grid;
  grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
}
.split--5-7 { grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); }
.split--8-4 { grid-template-columns: minmax(0, 8fr) minmax(0, 4fr); }
.split > * { min-width: 0; }

.pane { padding-block: var(--section-y); }
.pane--light { background-color: var(--color-surface); }
.pane--alt { background-color: var(--color-surface-alt); }
.pane--deep { background-color: var(--color-surface-deep); }
.pane--dark {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  background-image: repeating-linear-gradient(
    0deg,
    color-mix(in srgb, var(--color-contrast-accent) 6%, transparent) 0 1px,
    transparent 1px 5px
  );
}
.pane--dark h1, .pane--dark h2, .pane--dark h3, .pane--dark h4 { color: var(--color-contrast-ink); }
.pane--dark a { color: var(--color-contrast-accent); }
.pane--dark .rule-dotted { border-top-color: var(--color-contrast-line); }
.pane--dark .section-num { color: var(--color-contrast-accent); }

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

/* ============ 排版工具 ============ */
.prose {
  max-width: var(--measure);
  color: var(--color-ink);
}
.prose > * + * { margin-top: var(--space-2); }
.prose h2 { font-size: var(--text-2xl); margin-top: var(--space-6); }
.prose h3 { font-size: var(--text-xl); margin-top: var(--space-4); }
.prose p { margin: 0; }
.prose ul { list-style: none; }
.prose ul li {
  position: relative;
  padding-left: var(--space-3);
}
.prose ul li + li { margin-top: 6px; }
.prose ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.78em;
  width: 11px;
  height: var(--border-thin);
  background-color: var(--color-primary);
}
.pane--dark .prose,
.pane--dark .prose h2,
.pane--dark .prose h3 { color: var(--color-contrast-ink); }
.pane--dark .prose ul li::before { background-color: var(--color-contrast-accent); }

.lede {
  font-size: var(--text-lg);
  line-height: 1.55;
  color: var(--color-ink-soft);
  max-width: var(--measure);
}
.pane--dark .lede { color: color-mix(in srgb, var(--color-contrast-ink) 82%, transparent); }

.eyebrow {
  margin: 0 0 var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-primary);
}
.pane--dark .eyebrow { color: var(--color-contrast-accent); }

.section-num {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-4xl);
  font-weight: var(--weight-heading);
  line-height: 0.86;
  letter-spacing: -0.03em;
  color: var(--color-primary);
  font-variant-numeric: tabular-nums;
}

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

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

.note {
  font-size: var(--text-xs);
  line-height: 1.65;
  color: var(--color-ink-muted);
}
.pane--dark .note { color: color-mix(in srgb, var(--color-contrast-ink) 60%, transparent); }

.rule-dotted {
  border: 0;
  border-top: var(--border-thin) dashed var(--color-line);
  margin: var(--space-4) 0;
}
.rule-dotted--dark { border-top-color: var(--color-contrast-line); }

/* ============ 按钮 ============ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: 12px 22px;
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-md);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.02em;
  line-height: 1.2;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.16s ease, color 0.16s ease, border-color 0.16s ease;
}
.btn:disabled { opacity: 0.45; cursor: not-allowed; }

.btn--primary {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}
.btn--primary:hover {
  background-color: color-mix(in srgb, var(--color-primary) 84%, var(--color-contrast-surface));
  color: var(--color-primary-ink);
}

.btn--accent {
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.btn--accent:hover {
  background-color: color-mix(in srgb, var(--color-accent) 84%, var(--color-contrast-surface));
  color: var(--color-accent-ink);
}

.btn--ghost {
  background-color: transparent;
  border-color: var(--color-line);
  color: var(--color-ink);
}
.btn--ghost:hover {
  background-color: var(--color-surface-alt);
  border-color: var(--color-ink-soft);
  color: var(--color-ink);
}

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

.btn--sm {
  padding: 8px 14px;
  font-size: var(--text-xs);
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-4);
}

/* ============ 标签 ============ */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface);
  color: var(--color-ink-soft);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  line-height: 1.5;
  text-decoration: none;
  white-space: nowrap;
}
.tag--accent {
  border-color: color-mix(in srgb, var(--color-accent) 42%, var(--color-line));
  background-color: color-mix(in srgb, var(--color-highlight) 62%, var(--color-surface));
  color: color-mix(in srgb, var(--color-accent) 82%, var(--color-ink));
}
.tag--primary {
  border-color: transparent;
  background-color: var(--color-primary-soft);
  color: color-mix(in srgb, var(--color-primary) 74%, var(--color-ink));
}
.pane--dark .tag {
  background-color: transparent;
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
}
.pane--dark .tag--accent {
  border-color: color-mix(in srgb, var(--color-contrast-accent) 55%, var(--color-contrast-line));
  color: var(--color-contrast-accent);
}

/* ============ 读数面板 ============ */
.readout {
  display: grid;
  gap: 6px;
  padding: var(--space-3);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  background-color: var(--color-surface-alt);
}
.readout__label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  color: var(--color-ink-muted);
}
.readout__value {
  font-size: var(--text-3xl);
  font-weight: var(--weight-heading);
  line-height: 1;
  color: var(--color-ink);
}
.readout__unit {
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
  margin-left: 4px;
}
.readout--dark {
  background-color: var(--color-contrast-surface);
  background-image: repeating-linear-gradient(
    0deg,
    color-mix(in srgb, var(--color-contrast-accent) 7%, transparent) 0 1px,
    transparent 1px 5px
  );
  border-color: var(--color-contrast-line);
}
.readout--dark .readout__label { color: color-mix(in srgb, var(--color-contrast-ink) 58%, transparent); }
.readout--dark .readout__value { color: var(--color-contrast-accent); }
.readout--dark .readout__unit { color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent); }

.readout-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: var(--space-2);
}

/* ============ 图例式索引 ============ */
.legend {
  list-style: none;
  display: grid;
  gap: 0;
}
.legend li {
  display: grid;
  grid-template-columns: 14px minmax(0, 1fr) auto;
  align-items: baseline;
  gap: var(--space-2);
  padding: 10px 0;
  border-bottom: var(--border-thin) dotted var(--color-line);
  font-size: var(--text-sm);
}
.legend li:first-child { border-top: var(--border-thin) dotted var(--color-line); }
.legend__dot {
  width: 8px;
  height: 8px;
  border: var(--border-thin) solid var(--color-accent);
  border-radius: 50%;
  align-self: center;
}
.legend__meta {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  font-variant-numeric: tabular-nums;
}
.pane--dark .legend li { border-color: var(--color-contrast-line); color: var(--color-contrast-ink); }
.pane--dark .legend__dot { border-color: var(--color-contrast-accent); }
.pane--dark .legend__meta { color: color-mix(in srgb, var(--color-contrast-ink) 58%, transparent); }

/* ============ 图片容器 ============ */
.media-frame {
  position: relative;
  padding: var(--space-1);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  background-color: var(--color-surface-alt);
  overflow: hidden;
}
.media-frame > img,
.media-frame > .media-frame__box {
  width: 100%;
  display: block;
  border-radius: var(--radius-sm);
}
.media-frame__box {
  aspect-ratio: 16 / 9;
  background-color: var(--color-surface-deep);
  background-image: repeating-linear-gradient(
    45deg,
    color-mix(in srgb, var(--color-line) 60%, transparent) 0 1px,
    transparent 1px 12px
  );
}
.media-frame--dark {
  background-color: var(--color-contrast-surface);
  border-color: var(--color-contrast-line);
}
.media-frame--dark .media-frame__box {
  background-color: color-mix(in srgb, var(--color-contrast-surface) 82%, var(--color-contrast-accent));
  background-image: repeating-linear-gradient(
    45deg,
    color-mix(in srgb, var(--color-contrast-accent) 16%, transparent) 0 1px,
    transparent 1px 12px
  );
}
.media-frame__scrim {
  position: absolute;
  inset: var(--space-1);
  background: var(--overlay-scrim);
  border-radius: var(--radius-sm);
  pointer-events: none;
}
.media-frame__caption {
  position: absolute;
  left: calc(var(--space-1) + var(--space-3));
  right: calc(var(--space-1) + var(--space-3));
  bottom: calc(var(--space-1) + var(--space-3));
  z-index: 1;
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  line-height: 1.45;
}
.media-frame__caption .note { color: color-mix(in srgb, var(--color-contrast-ink) 72%, transparent); }

/* ============ 折叠内容组 ============ */
.accordion {
  border-top: var(--border-thin) solid var(--color-line);
}
.accordion-item {
  border-bottom: var(--border-thin) solid var(--color-line);
}
.accordion-head { margin: 0; font-size: inherit; }
.accordion-trigger {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) 18px;
  align-items: center;
  gap: var(--space-2);
  width: 100%;
  padding: var(--space-3) 0;
  border: 0;
  background: none;
  text-align: left;
  cursor: pointer;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  color: var(--color-ink);
  transition: color 0.14s ease;
}
.accordion-trigger:hover { color: var(--color-primary); }
.accordion-index {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  letter-spacing: 0.08em;
}
.accordion-marker {
  position: relative;
  width: 14px;
  height: 14px;
  justify-self: end;
}
.accordion-marker::before,
.accordion-marker::after {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  width: 100%;
  height: var(--border-thin);
  background-color: currentColor;
}
.accordion-marker::after {
  transform: rotate(90deg);
  transition: transform 0.2s ease, opacity 0.2s ease;
}
.accordion-item[data-open] .accordion-marker::after { transform: rotate(0deg); opacity: 0; }
.accordion-panel { padding: 0 0 var(--space-3) calc(var(--space-3) + 26px); }
.accordion-panel > .prose { max-width: var(--measure); }
.accordion[data-enhanced] .accordion-panel { display: none; }
.accordion[data-enhanced] .accordion-item[data-open] .accordion-panel { display: block; }

.pane--dark .accordion { border-top-color: var(--color-contrast-line); }
.pane--dark .accordion-item { border-bottom-color: var(--color-contrast-line); }
.pane--dark .accordion-trigger { color: var(--color-contrast-ink); }
.pane--dark .accordion-trigger:hover { color: var(--color-contrast-accent); }
.pane--dark .accordion-index { color: color-mix(in srgb, var(--color-contrast-ink) 52%, transparent); }

/* ============ 面包屑 ============ */
.breadcrumbs {
  font-size: var(--text-xs);
  letter-spacing: 0.04em;
  color: var(--color-ink-muted);
}
.breadcrumbs ol {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
}
.breadcrumbs li {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}
.breadcrumbs li + li::before {
  content: "/";
  color: var(--color-line);
}
.breadcrumbs a {
  color: var(--color-ink-soft);
  text-decoration: none;
}
.breadcrumbs a:hover { color: var(--color-primary); text-decoration: underline; }
.breadcrumbs [aria-current="page"] { color: var(--color-ink); }

/* ============ 头部 ============ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 70;
  background-color: color-mix(in srgb, var(--color-surface) 96%, transparent);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.skip-link {
  position: absolute;
  top: var(--space-1);
  left: var(--space-1);
  z-index: 200;
  padding: 10px 16px;
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border: var(--border-thin) solid var(--color-contrast-accent);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  text-decoration: none;
  transform: translateY(-220%);
  transition: transform 0.16s ease;
}
.skip-link:focus { transform: translateY(0); color: var(--color-contrast-ink); }

.header-support {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  background-image: repeating-linear-gradient(
    0deg,
    color-mix(in srgb, var(--color-contrast-accent) 7%, transparent) 0 1px,
    transparent 1px 5px
  );
  border-bottom: var(--border-thin) solid var(--color-contrast-line);
}
.support-inner {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding-block: 9px;
  font-size: var(--text-xs);
  letter-spacing: 0.04em;
}
.support-line {
  margin: 0;
  color: color-mix(in srgb, var(--color-contrast-ink) 76%, transparent);
}
.support-dot {
  flex: none;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background-color: var(--color-contrast-accent);
  animation: dot-breathe 2.4s ease-in-out infinite;
}
@keyframes dot-breathe {
  0%, 100% { opacity: 0.34; }
  50% { opacity: 1; }
}

.header-bar { padding-block: var(--space-3); }
.header-inner {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.brand-isle {
  display: inline-flex;
  flex-direction: column;
  gap: 1px;
  flex: none;
  padding: 9px var(--space-3);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-pill);
  background-color: var(--color-surface);
  text-decoration: none;
  transition: border-color 0.16s ease, background-color 0.16s ease;
}
.brand-isle:hover {
  border-color: color-mix(in srgb, var(--color-primary) 45%, var(--color-line));
  background-color: var(--color-surface-alt);
}
.brand-mark {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: 1.1;
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}
.brand-note {
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}

.nav-isle {
  margin-inline-start: auto;
  padding: 5px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-pill);
  background-color: var(--color-surface);
}
.nav-list {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 2px;
}
.nav-isle a {
  display: block;
  padding: 8px 13px;
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.14s ease, background-color 0.14s ease;
}
.nav-isle a:hover {
  color: var(--color-ink);
  background-color: var(--color-surface-alt);
}
.nav-isle a[aria-current="page"] {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}
.nav-foot { display: none; }

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  flex: none;
  position: relative;
  z-index: 20;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  padding: 9px 14px;
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border: var(--border-thin) solid var(--color-contrast-line);
  border-radius: var(--radius-pill);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: border-color 0.16s ease, color 0.16s ease;
}
.nav-toggle:hover {
  color: var(--color-contrast-accent);
  border-color: color-mix(in srgb, var(--color-contrast-accent) 55%, var(--color-contrast-line));
}
.nav-toggle-bars {
  position: relative;
  display: inline-block;
  width: 15px;
  height: 9px;
}
.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 100%;
  height: var(--border-thin);
  background-color: currentColor;
}
.nav-toggle-bars::before { top: 0; }
.nav-toggle-bars::after { bottom: 0; }

.scroll-meter {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 3px;
  overflow: hidden;
  background-color: transparent;
  pointer-events: none;
}
.scroll-meter__fill {
  display: block;
  height: 100%;
  width: 100%;
  transform: scaleX(var(--progress, 0));
  transform-origin: 0 50%;
  background-color: var(--color-accent);
  background-image: linear-gradient(90deg, var(--color-accent), var(--color-contrast-accent));
}

/* ============ 页脚 ============ */
.site-footer {
  margin-top: var(--section-y-lg);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  background-image: repeating-linear-gradient(
    0deg,
    color-mix(in srgb, var(--color-contrast-accent) 6%, transparent) 0 1px,
    transparent 1px 5px
  );
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) repeat(3, minmax(0, 1fr));
  gap: var(--space-6) var(--space-4);
  padding-block: var(--section-y) var(--space-8);
}

.footer-eyebrow {
  margin: 0 0 var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-contrast-accent);
}
.footer-closing {
  margin: 0 0 var(--space-4);
  max-width: 22ch;
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  color: var(--color-contrast-ink);
}

.footer-contact {
  margin: 0;
  display: grid;
  gap: 6px;
}
.footer-contact > div {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr);
  gap: var(--space-2);
  align-items: baseline;
}
.footer-contact dt {
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: color-mix(in srgb, var(--color-contrast-ink) 54%, transparent);
}
.footer-contact dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.7;
  color: var(--color-contrast-ink);
  word-break: break-word;
}

.footer-col h3 {
  margin: 0 0 var(--space-2);
  padding-bottom: var(--space-1);
  border-bottom: var(--border-thin) dashed var(--color-contrast-line);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.16em;
  color: color-mix(in srgb, var(--color-contrast-ink) 58%, transparent);
}
.footer-col ul { list-style: none; display: grid; gap: 2px; }
.footer-col a {
  display: block;
  padding: 8px 0;
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  text-decoration: none;
  border-bottom: var(--border-thin) solid transparent;
  transition: color 0.14s ease, border-color 0.14s ease;
}
.footer-col a:hover {
  color: var(--color-contrast-accent);
  border-bottom-color: color-mix(in srgb, var(--color-contrast-accent) 50%, transparent);
}

.footer-big {
  border-top: var(--border-thin) dashed var(--color-contrast-line);
  padding-block: var(--space-6) var(--space-2);
}
.footer-big-word {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-display);
  line-height: 0.88;
  letter-spacing: -0.03em;
  color: var(--color-contrast-ink);
  white-space: nowrap;
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-2);
  margin-top: var(--space-2);
  padding-block: var(--space-3) var(--space-6);
  border-top: var(--border-thin) solid var(--color-contrast-line);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.04em;
  color: color-mix(in srgb, var(--color-contrast-ink) 56%, transparent);
}

.site-footer :focus-visible,
.nav-isle[data-open] :focus-visible {
  outline-color: var(--color-contrast-accent);
}

/* ============ 响应式 ============ */
@media (max-width: 1080px) {
  .nav-isle { margin-inline-start: auto; }
  .nav-list { flex-wrap: wrap; }
}

@media (max-width: 1020px) {
  .nav-toggle { display: inline-flex; }

  .header-actions { margin-inline-start: auto; }

  .nav-isle {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    left: auto;
    z-index: 5;
    width: min(86vw, 360px);
    margin: 0;
    padding: calc(var(--space-8) + var(--space-6)) var(--space-3) var(--space-4);
    border: 0;
    border-left: var(--border-thin) solid var(--color-contrast-line);
    border-radius: 0;
    background-color: var(--color-contrast-surface);
    background-image: repeating-linear-gradient(
      0deg,
      color-mix(in srgb, var(--color-contrast-accent) 6%, transparent) 0 1px,
      transparent 1px 5px
    );
    overflow-y: auto;
    transform: translateX(101%);
    transition: transform 0.2s ease;
  }
  .nav-isle[data-open] { transform: translateX(0); }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }
  .nav-isle a {
    padding: 13px 4px;
    border-radius: 0;
    border-bottom: var(--border-thin) dashed var(--color-contrast-line);
    color: var(--color-contrast-ink);
    font-size: var(--text-lg);
  }
  .nav-isle a:hover {
    background-color: transparent;
    color: var(--color-contrast-accent);
  }
  .nav-isle a[aria-current="page"] {
    background-color: transparent;
    color: var(--color-contrast-accent);
    border-bottom-color: var(--color-contrast-accent);
  }

  .nav-foot {
    display: grid;
    gap: 4px;
    margin: var(--space-3) 0 0;
    padding-top: var(--space-3);
    font-family: var(--font-mono);
    font-size: var(--text-xs);
    line-height: 1.7;
    color: color-mix(in srgb, var(--color-contrast-ink) 60%, transparent);
  }

  .split,
  .split--5-7,
  .split--8-4 { grid-template-columns: minmax(0, 1fr); }

  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 900px) {
  .span-3, .span-4, .span-5, .span-6, .span-7, .span-8, .span-9 { grid-column: span 12; }
  .pane { padding-block: var(--section-y); }
  .section--lg { padding-block: var(--section-y); }
}

@media (max-width: 680px) {
  .header-bar { padding-block: var(--space-2); }
  .brand-note { display: none; }
  .header-cta { display: none; }
  .support-inner { align-items: flex-start; padding-block: 8px; }
  .support-line { font-size: var(--text-xs); line-height: 1.6; }

  .footer-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--space-4);
    padding-block: var(--section-y) var(--space-6);
  }
  .footer-contact > div { grid-template-columns: 68px minmax(0, 1fr); }
  .footer-legal { flex-direction: column; align-items: flex-start; }
  .accordion-panel { padding-left: 0; }
}

/* ============ 动效降级 ============ */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
  .support-dot { opacity: 1; }
}