/* ============================================================
   家乐棋牌汇 · 共享样式 /assets/site.css
   复古出版印刷 × 电竞战情室
   ============================================================ */

:root {
  --color-surface: #f4f3f2;
  --color-surface-alt: #eceae9;
  --color-surface-deep: #e0dedc;
  --color-ink: #4a433b;
  --color-ink-soft: #73695e;
  --color-ink-muted: #8b8074;
  --color-line: #d5d3d1;
  --color-primary: #9e6b33;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #e8e0d7;
  --color-accent: #9e6a0f;
  --color-accent-ink: #ffffff;
  --color-highlight: #e5dac9;
  --color-focus: #935f06;
  --color-contrast-surface: #18140f;
  --color-contrast-ink: #e7e6e4;
  --color-contrast-line: #46423e;
  --color-contrast-accent: #e99c16;
  --overlay-scrim: linear-gradient(180deg, rgba(24, 20, 15, 0.35) 0%, rgba(24, 20, 15, 0.72) 55%, rgba(24, 20, 15, 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: 11.0px;
  --text-sm: 14.7px;
  --text-base: 17px;
  --text-lg: 22.7px;
  --text-xl: 30.2px;
  --text-2xl: 40.3px;
  --text-3xl: 53.7px;
  --text-4xl: 71.5px;
  --text-display: clamp(37px, 7.7vw, 98px);
  --text-figure: clamp(31px, 5.5vw, 71px);
  --weight-heading: 634;
  --weight-body: 400;
  --leading-body: 1.7;
  --leading-heading: 1.3;
  --tracking-heading: 0.01em;
  --radius-sm: 1px;
  --radius-md: 1px;
  --radius-lg: 1px;
  --radius-pill: 1px;
  --border-thin: 1px;
  --border-thick: 3px;
  --shadow-1: 0 1px 0 rgba(74, 67, 59, 0.12);
  --shadow-2: 0 2px 0 rgba(74, 67, 59, 0.18);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1160px;
  --measure: 67ch;
  --gutter: 16px;
  --section-y: 78px;
  --section-y-lg: 109px;
}

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body { margin: 0; }
h1, h2, h3, h4, h5, h6, p, figure, blockquote, ul, ol, dl, dd { margin: 0; }
ul, ol { padding: 0; list-style: none; }
img, svg, video { display: block; max-width: 100%; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
table { border-collapse: collapse; width: 100%; }
hr { border: 0; margin: 0; }

/* ---------- base ---------- */
body {
  background-color: var(--color-surface);
  background-image: radial-gradient(rgba(74, 67, 59, 0.05) 0.5px, transparent 0.5px);
  background-size: 6px 6px;
  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: 0.01em;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

h1, h2, h3, h4 {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
  text-wrap: balance;
}
h1 { font-size: var(--text-2xl); }
h2 { font-size: var(--text-xl); }
h3 { font-size: var(--text-lg); }
h4 { font-size: var(--text-base); }
p { line-height: var(--leading-body); }
.prose p { max-width: var(--measure); }
.prose p + p { margin-top: var(--space-2); }
.prose h2 { margin-top: var(--space-6); margin-bottom: var(--space-2); }
.prose h3 { margin-top: var(--space-4); margin-bottom: var(--space-1); }
.prose ul, .prose ol { margin: var(--space-2) 0; padding-left: var(--space-3); max-width: var(--measure); }
.prose ul { list-style: square; }
.prose ol { list-style: decimal; }
.prose li + li { margin-top: var(--space-1); }

a {
  color: var(--color-accent);
  text-decoration: none;
  border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-accent) 40%, transparent);
  transition: color 0.18s ease, border-color 0.18s ease;
}
a:hover { color: var(--color-focus); border-bottom-color: var(--color-focus); }

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

:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}
.site-header :focus-visible { outline-color: var(--color-contrast-accent); }
.site-header[data-scrolled="true"] :focus-visible { outline-color: var(--color-focus); }
.site-footer :focus-visible,
.dark-band :focus-visible { outline-color: var(--color-contrast-accent); }

/* ---------- skip link ---------- */
.skip-link {
  position: fixed;
  left: var(--space-2);
  top: -80px;
  z-index: 200;
  padding: var(--space-2) var(--space-3);
  background: var(--color-accent);
  color: var(--color-accent-ink);
  border: var(--border-thin) solid var(--color-contrast-surface);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  border-bottom-style: solid;
  transition: top 0.18s ease;
}
.skip-link:focus { top: var(--space-2); color: var(--color-accent-ink); }

/* ---------- layout helpers ---------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--space-3);
}
.section { padding-block: var(--section-y); }
.section--lg { padding-block: var(--section-y-lg); }
.section--alt { background: var(--color-surface-alt); }
.section--tight { padding-block: var(--space-6); }

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

/* ---------- section heads ---------- */
.section-head {
  display: grid;
  justify-items: center;
  text-align: center;
  gap: var(--space-1);
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-3);
  border-bottom: var(--border-thick) double var(--color-line);
}
.section-kicker {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.22em;
  color: var(--color-accent);
}
.section-title { margin: 0; }
.section-sub {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  max-width: 52ch;
}
.lede {
  font-size: var(--text-lg);
  line-height: 1.6;
  color: var(--color-ink-soft);
  max-width: 52ch;
}

/* ---------- rules & dividers ---------- */
.rule {
  border-top: var(--border-thin) dashed var(--color-line);
  margin-block: var(--space-4);
}
.rule--double {
  height: 5px;
  border-top: var(--border-thin) solid var(--color-line);
  border-bottom: var(--border-thin) solid var(--color-line);
  margin-block: var(--space-4);
}
.dark-band .rule { border-top-color: var(--color-contrast-line); }
.dark-band .rule--double {
  border-top-color: var(--color-contrast-line);
  border-bottom-color: var(--color-contrast-line);
}

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 10px var(--space-3);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  border: var(--border-thin) solid var(--color-ink);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  color: var(--color-ink);
  cursor: pointer;
  transition: background-color 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}
.btn:hover {
  background: var(--color-primary-soft);
  border-color: var(--color-primary);
  color: var(--color-ink);
}
.btn--primary {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.btn--primary:hover {
  background: var(--color-focus);
  border-color: var(--color-focus);
  color: var(--color-accent-ink);
}
.btn--ghost {
  background: transparent;
  border-color: currentColor;
  color: inherit;
}
.btn--ghost:hover {
  background: color-mix(in srgb, currentColor 14%, transparent);
  border-color: currentColor;
  color: inherit;
}

/* ---------- tickets & figures ---------- */
.ticket {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 3px var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-primary);
  background: var(--color-primary-soft);
  border: var(--border-thin) dashed var(--color-primary);
  border-radius: var(--radius-sm);
}
.ticket--accent {
  color: var(--color-accent-ink);
  background: var(--color-accent);
  border-color: var(--color-accent);
  border-style: solid;
}
.ticket--dark {
  color: var(--color-contrast-accent);
  background: transparent;
  border-color: var(--color-contrast-accent);
}

.figure-value {
  font-family: var(--font-mono);
  font-size: var(--text-xl);
  line-height: 1.1;
  letter-spacing: -0.01em;
  font-variant-numeric: tabular-nums;
  color: var(--color-ink);
}
.figure-unit {
  font-family: var(--font-body);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  margin-left: 4px;
  letter-spacing: 0.06em;
}
.dark-band .figure-value { color: var(--color-contrast-accent); }
.dark-band .figure-unit { color: var(--color-contrast-ink); opacity: 0.7; }

/* ---------- breadcrumb ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  padding-block: var(--space-2);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}
.breadcrumb li { display: inline-flex; align-items: center; }
.breadcrumb li + li::before {
  content: "／";
  margin-right: var(--space-1);
  color: var(--color-line);
}
.breadcrumb a { color: var(--color-ink-soft); border-bottom: 0; }
.breadcrumb a:hover { color: var(--color-accent); }
.breadcrumb [aria-current="page"] { color: var(--color-accent); }

/* ---------- quote block ---------- */
.quote-block {
  position: relative;
  margin-block: var(--space-4);
  padding: var(--space-4) var(--space-4) var(--space-4) var(--space-6);
  background: var(--color-highlight);
  border-left: var(--border-thick) solid var(--color-accent);
  border-radius: var(--radius-sm);
}
.quote-block::before {
  content: "“";
  position: absolute;
  left: var(--space-2);
  top: var(--space-1);
  font-family: var(--font-heading);
  font-size: var(--text-2xl);
  line-height: 1;
  color: var(--color-accent);
}
.quote-block p { font-size: var(--text-lg); max-width: 46ch; }
.dark-band .quote-block {
  background: color-mix(in srgb, var(--color-contrast-accent) 12%, transparent);
  border-left-color: var(--color-contrast-accent);
}
.dark-band .quote-block::before { color: var(--color-contrast-accent); }

/* ---------- media frames (图片占位，页面阶段填图) ---------- */
.media-frame {
  position: relative;
  display: block;
  background: var(--color-surface-deep);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  overflow: hidden;
}
.media-frame img { width: 100%; height: 100%; object-fit: cover; }
.media-frame--wide { aspect-ratio: 16 / 9; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame--square { aspect-ratio: 1 / 1; }
.media-frame--scrim::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--overlay-scrim);
  pointer-events: none;
}
.media-caption {
  position: absolute;
  left: 0;
  bottom: 0;
  z-index: 2;
  max-width: calc(100% - var(--space-4));
  padding: 6px var(--space-2);
  background: var(--color-surface);
  color: var(--color-ink);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  border-top: var(--border-thin) solid var(--color-line);
  border-right: var(--border-thin) solid var(--color-line);
}
.dark-band .media-frame { border-color: var(--color-contrast-line); }

/* ---------- panels ---------- */
.panel {
  display: grid;
  grid-template-rows: 0fr;
  opacity: 0;
  visibility: hidden;
  transition: grid-template-rows 0.18s ease, opacity 0.18s ease, visibility 0.18s;
}
.panel[data-open="true"] {
  grid-template-rows: 1fr;
  opacity: 1;
  visibility: visible;
}
.panel-body { overflow: hidden; min-height: 0; padding-top: var(--space-2); }
.panel-toggle {
  display: flex;
  width: 100%;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  text-align: left;
  font-size: var(--text-sm);
  letter-spacing: 0.04em;
  color: var(--color-ink);
  background: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  transition: background-color 0.18s ease, border-color 0.18s ease;
}
.panel-toggle::after {
  content: "＋";
  font-family: var(--font-mono);
  color: var(--color-accent);
  flex: none;
}
.panel-toggle[aria-expanded="true"]::after { content: "－"; }
.panel-toggle:hover {
  background: var(--color-primary-soft);
  border-color: var(--color-primary);
}
.dark-band .panel-toggle {
  background: color-mix(in srgb, var(--color-contrast-surface) 80%, var(--color-contrast-line));
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
}
.dark-band .panel-toggle:hover { border-color: var(--color-contrast-accent); }

/* ---------- data tables ---------- */
.table-scroll {
  overflow-x: auto;
  border: var(--border-thin) solid var(--color-line);
  background: var(--color-surface);
  border-radius: var(--radius-sm);
}
.data-table { min-width: 640px; font-size: var(--text-sm); }
.data-table th,
.data-table td {
  padding: 10px var(--space-2);
  text-align: left;
  vertical-align: top;
  border-bottom: var(--border-thin) solid var(--color-line);
}
.data-table thead th {
  background: var(--color-surface-deep);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  letter-spacing: 0.04em;
  border-bottom: var(--border-thick) double var(--color-line);
}
.data-table tbody tr:nth-child(even) { background: var(--color-surface-alt); }
.data-table th:first-child,
.data-table td:first-child {
  position: sticky;
  left: 0;
  z-index: 1;
  background: var(--color-surface-deep);
  border-right: var(--border-thin) dashed var(--color-line);
}
.data-table td.num {
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  font-variant-numeric: tabular-nums;
  color: var(--color-accent);
  letter-spacing: -0.01em;
}
.dark-band .table-scroll { background: var(--color-contrast-surface); border-color: var(--color-contrast-line); }
.dark-band .data-table { color: var(--color-contrast-ink); }
.dark-band .data-table th,
.dark-band .data-table td { border-bottom-color: var(--color-contrast-line); }
.dark-band .data-table thead th {
  background: color-mix(in srgb, var(--color-contrast-line) 45%, var(--color-contrast-surface));
  border-bottom-color: var(--color-contrast-accent);
  color: var(--color-contrast-ink);
}
.dark-band .data-table tbody tr:nth-child(even) {
  background: color-mix(in srgb, var(--color-contrast-line) 22%, var(--color-contrast-surface));
}
.dark-band .data-table th:first-child,
.dark-band .data-table td:first-child {
  background: color-mix(in srgb, var(--color-contrast-line) 30%, var(--color-contrast-surface));
  color: var(--color-contrast-ink);
}
.dark-band .data-table td.num { color: var(--color-contrast-accent); }

/* ---------- timeline strip ---------- */
.timeline-strip {
  display: flex;
  gap: var(--space-3);
  overflow-x: auto;
  padding: var(--space-3);
  cursor: grab;
  border-top: var(--border-thick) double var(--color-line);
  border-bottom: var(--border-thick) double var(--color-line);
  scrollbar-width: thin;
}
.timeline-strip[data-dragging="true"] { cursor: grabbing; }
.timeline-strip::-webkit-scrollbar { height: 6px; }
.timeline-strip::-webkit-scrollbar-thumb { background: var(--color-line); }
.timeline-item {
  flex: 0 0 auto;
  min-width: 220px;
  padding: var(--space-2) var(--space-3);
  background: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
}
.timeline-item .ticket { margin-bottom: var(--space-1); }
.timeline-item h3 { font-size: var(--text-lg); }
.timeline-item p { font-size: var(--text-sm); color: var(--color-ink-soft); }
.dark-band .timeline-strip { border-color: var(--color-contrast-line); }
.dark-band .timeline-item {
  background: color-mix(in srgb, var(--color-contrast-line) 30%, var(--color-contrast-surface));
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
}

/* ---------- section nav ---------- */
.section-nav {
  position: sticky;
  top: 96px;
  display: grid;
  gap: 2px;
  font-size: var(--text-sm);
}
.section-nav a {
  display: block;
  padding: 6px var(--space-2);
  color: var(--color-ink-soft);
  border-bottom: 0;
  border-left: var(--border-thick) double var(--color-line);
  transition: color 0.18s ease, background-color 0.18s ease, border-color 0.18s ease;
}
.section-nav a:hover { color: var(--color-accent); background: var(--color-surface-alt); }
.section-nav a[data-current="true"] {
  color: var(--color-accent);
  background: var(--color-primary-soft);
  border-left-color: var(--color-accent);
}

/* ---------- dark band ---------- */
.dark-band {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  padding-block: var(--section-y);
}
.dark-band h1,
.dark-band h2,
.dark-band h3,
.dark-band h4 { color: var(--color-contrast-ink); }
.dark-band a {
  color: var(--color-contrast-accent);
  border-bottom-color: color-mix(in srgb, var(--color-contrast-accent) 45%, transparent);
}
.dark-band a:hover { color: var(--color-contrast-accent); border-bottom-color: var(--color-contrast-accent); }
.dark-band .section-kicker { color: var(--color-contrast-accent); }
.dark-band .section-head { border-bottom-color: var(--color-contrast-line); }
.dark-band .lede { color: var(--color-contrast-ink); opacity: 0.82; }

/* ---------- back to top ---------- */
.back-to-top {
  position: fixed;
  right: var(--space-3);
  bottom: var(--space-3);
  z-index: 90;
  padding: 10px var(--space-3);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border: var(--border-thin) solid var(--color-contrast-accent);
  border-radius: var(--radius-sm);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity 0.18s ease, transform 0.18s ease, visibility 0.18s;
}
.back-to-top[data-visible="true"] { opacity: 1; visibility: visible; transform: none; }
.back-to-top:hover {
  background: var(--color-contrast-accent);
  color: var(--color-contrast-surface);
}

/* ============================================================
   头部
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  color: var(--color-contrast-ink);
  border-bottom: var(--border-thin) solid transparent;
  transition: background-color 0.24s ease, color 0.24s ease, border-color 0.24s ease;
}
.site-header[data-scrolled="false"] {
  background-color: transparent;
  background-image: linear-gradient(
    180deg,
    color-mix(in srgb, var(--color-contrast-surface) 78%, transparent) 0%,
    color-mix(in srgb, var(--color-contrast-surface) 0%, transparent) 100%
  );
}
.site-header[data-scrolled="true"] {
  background-color: var(--color-surface);
  background-image: none;
  color: var(--color-ink);
  border-bottom-color: var(--color-line);
}
.header-bar { position: relative; }
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-2) var(--space-3);
}
.brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  min-width: 0;
  color: inherit;
  border-bottom: 0;
}
.brand:hover { color: inherit; border-bottom: 0; }
.brand-mark {
  display: grid;
  place-items: center;
  flex: none;
  width: 38px;
  height: 38px;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: 1;
  color: var(--color-accent-ink);
  background: var(--color-accent);
  border-radius: var(--radius-sm);
  outline: var(--border-thin) solid color-mix(in srgb, var(--color-accent-ink) 62%, transparent);
  outline-offset: -4px;
}
.brand-copy { display: flex; flex-direction: column; gap: 2px; min-width: 0; }
.brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: 1.1;
  letter-spacing: 0.08em;
  color: inherit;
}
.brand-line {
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: currentColor;
  opacity: 0.72;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  flex: none;
  padding: var(--space-1) var(--space-2);
  font-size: var(--text-sm);
  letter-spacing: 0.1em;
  color: inherit;
  background: transparent;
  border: var(--border-thin) solid currentColor;
  border-radius: var(--radius-sm);
}
.nav-toggle-mark {
  position: relative;
  display: block;
  width: 14px;
  height: 9px;
  border-top: var(--border-thin) solid currentColor;
  border-bottom: var(--border-thin) solid currentColor;
}
.nav-toggle-mark::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 3px;
  border-top: var(--border-thin) solid currentColor;
}
.nav-toggle[aria-expanded="true"] {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.site-nav {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  flex: 1 1 auto;
  gap: var(--space-4);
}
.nav-list { display: flex; align-items: center; gap: var(--space-3); }
.nav-item { position: relative; }
.nav-link {
  position: relative;
  display: inline-block;
  padding: 6px 2px 8px;
  font-size: var(--text-base);
  letter-spacing: 0.05em;
  color: inherit;
  border-bottom: 0;
}
.nav-link:hover { color: inherit; border-bottom: 0; }
.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 3px;
  border-top: var(--border-thin) solid currentColor;
  border-bottom: var(--border-thin) solid currentColor;
  opacity: 0;
  transition: opacity 0.18s ease;
}
.nav-link:hover::after,
.nav-link:focus-visible::after { opacity: 0.5; }
.site-nav .nav-link[aria-current="page"] { font-weight: 600; }
.site-nav .nav-link[aria-current="page"]::after { opacity: 1; }
.site-header[data-scrolled="true"] .nav-link[aria-current="page"] { color: var(--color-accent); }
.nav-tools { display: flex; align-items: center; gap: var(--space-2); }
.nav-chip {
  display: inline-block;
  padding: 5px var(--space-2);
  font-size: var(--text-sm);
  letter-spacing: 0.05em;
  color: inherit;
  background: transparent;
  border: var(--border-thin) dashed currentColor;
  border-radius: var(--radius-sm);
  transition: background-color 0.18s ease;
}
.nav-chip:hover {
  background: color-mix(in srgb, currentColor 14%, transparent);
  color: inherit;
  border-color: currentColor;
}
.nav-cta { white-space: nowrap; }
.scroll-progress {
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 2px;
  background: var(--color-accent);
  transform: scaleX(0);
  transform-origin: 0 50%;
  opacity: 0.95;
}

/* ============================================================
   页脚
   ============================================================ */
.site-footer {
  margin-top: var(--space-8);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
}
.footer-tier { padding-block: var(--space-6); }
.footer-tier + .footer-tier {
  border-top: var(--border-thick) double var(--color-contrast-line);
}
.footer-tier--contact { padding-block: var(--space-4); }
.footer-tier--legal { padding-block: var(--space-3); }

.footer-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr;
  gap: var(--space-6);
}
.footer-brand { display: flex; flex-direction: column; gap: var(--space-1); }
.footer-brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  letter-spacing: 0.08em;
  color: var(--color-contrast-ink);
}
.footer-tagline {
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-contrast-ink);
  opacity: 0.62;
}
.footer-note {
  margin-top: var(--space-1);
  max-width: 34ch;
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-contrast-ink);
  opacity: 0.78;
}
.footer-heading {
  margin-bottom: var(--space-2);
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.22em;
  color: var(--color-contrast-accent);
}
.footer-links { display: grid; gap: var(--space-1); }
.footer-links a {
  display: inline-block;
  padding-bottom: 2px;
  color: var(--color-contrast-ink);
  border-bottom: var(--border-thin) dashed color-mix(in srgb, var(--color-contrast-accent) 52%, transparent);
  transition: color 0.18s ease, border-color 0.18s ease;
}
.footer-links a:hover {
  color: var(--color-contrast-accent);
  border-bottom-color: var(--color-contrast-accent);
}
.footer-contact { display: grid; gap: var(--space-2); }
.contact-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 260px), 1fr));
  gap: var(--space-2) var(--space-4);
}
.contact-item {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1) var(--space-2);
  padding-block: var(--space-1);
  border-bottom: var(--border-thin) dashed var(--color-contrast-line);
}
.contact-label {
  flex: none;
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-contrast-accent);
}
.contact-value {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.02em;
  color: var(--color-contrast-ink);
  word-break: break-word;
}
.copy-btn {
  flex: none;
  padding: 3px var(--space-1);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-contrast-accent);
  background: transparent;
  border: var(--border-thin) dashed var(--color-contrast-accent);
  border-radius: var(--radius-sm);
  transition: background-color 0.18s ease, color 0.18s ease;
}
.copy-btn:hover {
  background: var(--color-contrast-accent);
  color: var(--color-contrast-surface);
}
.copy-hint {
  flex: none;
  padding: 2px 6px;
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-contrast-surface);
  background: var(--color-contrast-accent);
  border-radius: var(--radius-sm);
  opacity: 0;
  transform: translateY(-2px);
  transition: opacity 0.18s ease, transform 0.18s ease;
}
.copy-hint[data-visible="true"] { opacity: 1; transform: none; }

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2) var(--space-4);
}
.legal-copy {
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-contrast-ink);
  opacity: 0.7;
}
.legal-copy--muted { opacity: 0.55; }
.legal-links { display: flex; flex-wrap: wrap; gap: var(--space-3); }
.legal-links a {
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-contrast-ink);
  opacity: 0.85;
  border-bottom: 0;
}
.legal-links a:hover { color: var(--color-contrast-accent); opacity: 1; }

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 1024px) {
  .brand-line { max-width: 220px; }
  .nav-list { gap: var(--space-2); }
  .site-nav { gap: var(--space-3); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 900px) {
  .site-header {
    background-color: var(--color-surface);
    background-image: none;
    color: var(--color-ink);
    border-bottom: var(--border-thin) solid var(--color-line);
  }
  .nav-toggle { display: inline-flex; }
  .site-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: grid;
    justify-items: stretch;
    justify-content: stretch;
    gap: var(--space-3);
    padding: var(--space-3);
    background: var(--color-surface);
    color: var(--color-ink);
    border-top: var(--border-thin) solid var(--color-line);
    border-bottom: var(--border-thick) double var(--color-line);
    box-shadow: var(--shadow-2);
    visibility: hidden;
    opacity: 0;
    transform: translateY(-8px);
    transition: opacity 0.2s ease, transform 0.2s ease, visibility 0.2s;
  }
  .site-nav[data-open="true"] {
    visibility: visible;
    opacity: 1;
    transform: none;
  }
  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }
  .nav-item { border-bottom: var(--border-thin) dashed var(--color-line); }
  .nav-link { display: block; padding: var(--space-2) 0; }
  .nav-link::after { display: none; }
  .site-nav .nav-link[aria-current="page"] {
    color: var(--color-accent);
    padding-left: var(--space-2);
    border-left: var(--border-thick) double var(--color-accent);
  }
  .nav-tools {
    flex-wrap: wrap;
    justify-content: flex-start;
    gap: var(--space-2);
  }
  .nav-cta { width: 100%; }
  .section-nav {
    position: static;
    grid-auto-flow: column;
    grid-auto-columns: max-content;
    overflow-x: auto;
    padding-bottom: var(--space-1);
  }
  .section-nav a { border-left: 0; border-bottom: var(--border-thick) double var(--color-line); }
  .section-nav a[data-current="true"] { border-bottom-color: var(--color-accent); }
}

@media (max-width: 640px) {
  .header-inner { padding: var(--space-2) var(--space-2); gap: var(--space-2); }
  .brand-line { display: none; }
  .brand-mark { width: 32px; height: 32px; font-size: var(--text-base); }
  .brand-name { font-size: var(--text-base); }
  .container { padding-inline: var(--space-2); }
  .section { padding-block: var(--space-6); }
  .section--lg { padding-block: var(--space-8); }
  .footer-grid { grid-template-columns: 1fr; gap: var(--space-4); }
  .footer-tier { padding-block: var(--space-4); }
  .footer-legal { justify-content: flex-start; }
  .lead, .lede { font-size: var(--text-base); }
  .grid--12 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .col-4, .col-6, .col-8, .col-12 { grid-column: span 4; }
  .back-to-top { right: var(--space-2); bottom: var(--space-2); }
}

/* ============================================================
   动效与无障碍
   ============================================================ */
@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;
  }
  .site-nav { transform: none; }
  .back-to-top { transform: none; }
  .copy-hint { transform: none; }
}