/* =========================================================
   得乐投注站 · 共享样式表  /assets/site.css
   骨架：左右分屏 · 透明叠加导航 · 墨夜蓝黑 × 高原雾白 × 晴空蓝
   ========================================================= */

/* ---------- 1. Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  -webkit-tap-highlight-color: transparent;
  scroll-behavior: smooth;
}

body,
h1, h2, h3, h4, h5, p, ul, ol, li, figure, blockquote, dl, dd, caption, table {
  margin: 0;
  padding: 0;
}

ul, ol { list-style: none; }

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

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  cursor: pointer;
}

a { color: inherit; text-decoration: none; }

table { border-collapse: collapse; }

/* ---------- 2. Tokens ---------- */
:root {
  --ink: #0E1B1F;
  --deep: #12414A;
  --mist: #F4F7F6;
  --sky: #1E7A8C;
  --terra: #159C8C;
  --amber: #E8A33D;
  --amber-deep: #B4761B;
  --slate: #5B6E72;
  --line: #C9D6D8;
  --white: #FFFFFF;

  --header-h: 72px;
  --gutter: clamp(18px, 4vw, 56px);
  --maxw: 1200px;
  --maxw-wide: 1400px;
  --maxw-narrow: 820px;

  --r-xl: 32px;
  --r-lg: 20px;
  --r-md: 14px;
  --r-pill: 999px;

  --font-sans: "Source Han Sans SC", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-serif: "Source Han Serif SC", "Noto Serif SC", "Songti SC", "SimSun", Georgia, serif;
  --font-mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Mono", Consolas, "Courier New", monospace;

  --step: 96px;
  --shadow-soft: 0 24px 60px -44px rgba(14, 27, 31, .65);
}

/* ---------- 3. Base typography ---------- */
body {
  min-height: 100vh;
  background: var(--mist);
  color: var(--ink);
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 1.85;
  letter-spacing: .01em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5 {
  font-family: var(--font-sans);
  font-weight: 800;
  line-height: 1.22;
  letter-spacing: -.01em;
}

h4, h5 { font-weight: 600; letter-spacing: .01em; }

strong, b { font-weight: 700; }

::selection { background: var(--sky); color: var(--white); }

#main-content {
  display: block;
  scroll-margin-top: calc(var(--header-h) + 16px);
}

/* ---------- 4. Focus ---------- */
:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 5. Skip link ---------- */
.skip-link {
  position: fixed;
  left: 16px;
  top: -80px;
  z-index: 200;
  padding: 12px 22px;
  border-radius: var(--r-pill);
  background: var(--amber);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .04em;
  line-height: 1;
  transition: top 180ms linear;
}

.skip-link:focus {
  top: 14px;
  outline-color: var(--ink);
}

/* ---------- 6. Layout containers ---------- */
.wrap {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding-left: var(--gutter);
  padding-right: var(--gutter);
}

.wrap--narrow { max-width: var(--maxw-narrow); }
.wrap--wide { max-width: var(--maxw-wide); }

/* ---------- 7. Site header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  margin-bottom: calc(-1 * var(--header-h));
  background-color: rgba(14, 27, 31, .82);
  -webkit-backdrop-filter: blur(10px) saturate(130%);
  backdrop-filter: blur(10px) saturate(130%);
  transition: background-color 260ms linear, box-shadow 260ms linear;
}

.site-header[data-scrolled] {
  background-color: var(--deep);
  box-shadow: 0 1px 0 rgba(201, 214, 216, .22), 0 18px 34px -30px rgba(14, 27, 31, .95);
}

.header__inner {
  display: flex;
  align-items: center;
  gap: 18px;
  min-height: var(--header-h);
}

/* brand */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  color: var(--white);
}

.brand__mark {
  width: 26px;
  height: 26px;
  border-radius: 9px;
  flex: 0 0 auto;
  background: conic-gradient(from 210deg, var(--sky) 0deg 120deg, var(--terra) 120deg 240deg, var(--amber) 240deg 360deg);
  box-shadow: inset 0 0 0 2px rgba(244, 247, 246, .46);
}

.brand__text {
  font-family: var(--font-sans);
  font-size: 19px;
  font-weight: 800;
  letter-spacing: .06em;
  color: var(--white);
}

.brand__tagline {
  padding-left: 12px;
  border-left: 1px solid rgba(201, 214, 216, .3);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  color: rgba(244, 247, 246, .62);
}

/* version badge */
.version-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-left: 4px;
  padding: 5px 13px;
  border: 1px solid rgba(232, 163, 61, .55);
  border-radius: var(--r-pill);
  background: rgba(232, 163, 61, .12);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  white-space: nowrap;
}

.version-badge__key { color: rgba(232, 163, 61, .82); }
.version-badge__num { color: var(--amber); font-weight: 700; }

/* nav toggle */
.nav__toggle {
  display: none;
  align-items: center;
  gap: 9px;
  margin-left: auto;
  padding: 9px 15px;
  border: 1px solid rgba(201, 214, 216, .42);
  border-radius: var(--r-pill);
  color: var(--white);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
}

.nav__toggle-bars {
  position: relative;
  width: 16px;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
}

.nav__toggle-bars::before,
.nav__toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 16px;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: transform 200ms linear;
}

.nav__toggle-bars::before { top: -5px; }
.nav__toggle-bars::after { top: 5px; }

.site-header[data-open] .nav__toggle-bars { background: transparent; }
.site-header[data-open] .nav__toggle-bars::before { transform: translateY(5px) rotate(45deg); }
.site-header[data-open] .nav__toggle-bars::after { transform: translateY(-5px) rotate(-45deg); }

/* nav */
.nav {
  display: flex;
  align-items: center;
  gap: 20px;
  margin-left: auto;
}

.nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
}

.nav__item { display: block; }

.nav__link {
  position: relative;
  display: inline-block;
  padding: 9px 12px;
  border-radius: var(--r-pill);
  color: rgba(244, 247, 246, .82);
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: .02em;
  line-height: 1.3;
  transition: color 160ms linear, background-color 160ms linear;
}

.nav__link:hover {
  color: var(--white);
  background: rgba(30, 122, 140, .28);
}

.nav__link[aria-current="page"] { color: var(--white); }

.nav__link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 2px;
  height: 2px;
  border-radius: 2px;
  background: var(--sky);
}

.nav__utility {
  display: flex;
  align-items: center;
  gap: 16px;
  padding-left: 20px;
  border-left: 1px solid rgba(201, 214, 216, .26);
}

.nav__util-link {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: rgba(244, 247, 246, .66);
  transition: color 160ms linear;
}

.nav__util-link:hover {
  color: var(--white);
  text-decoration: underline;
  text-decoration-color: var(--sky);
  text-underline-offset: 4px;
}

/* scroll progress */
.scroll-progress {
  height: 2px;
  width: 100%;
  opacity: 0;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--sky) 0%, var(--terra) 58%, var(--amber) 100%);
  transition: transform 90ms linear, opacity 200ms linear;
}

.site-header[data-scrolled] .scroll-progress { opacity: 1; }

/* ---------- 8. Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 24px;
  border: 1px solid transparent;
  border-radius: var(--r-pill);
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .04em;
  line-height: 1;
  white-space: nowrap;
  transition: background-color 180ms linear, color 180ms linear, border-color 180ms linear;
}

.btn--primary {
  background: var(--sky);
  color: var(--white);
}

.btn--primary:hover { background: var(--terra); }

.btn--ghost {
  background: transparent;
  border-color: rgba(201, 214, 216, .42);
  color: var(--white);
}

.btn--ghost:hover {
  background: rgba(30, 122, 140, .24);
  border-color: var(--sky);
}

.btn--outline {
  background: transparent;
  border-color: var(--line);
  color: var(--ink);
}

.btn--outline:hover {
  border-color: var(--sky);
  color: var(--sky);
}

.btn--sm {
  padding: 9px 17px;
  font-size: 13.5px;
}

/* ---------- 9. Sections ---------- */
.section {
  padding-top: var(--step);
  padding-bottom: var(--step);
}

.section--tight {
  padding-top: 64px;
  padding-bottom: 64px;
}

.section--mist { background: var(--mist); }
.section--dark { background: var(--ink); color: rgba(244, 247, 246, .82); }
.section--deep { background: var(--deep); color: rgba(244, 247, 246, .82); }

.section__head { max-width: 760px; }

.section__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--sky);
}

.section__eyebrow::before {
  content: "";
  width: 26px;
  height: 1px;
  background: currentColor;
}

.section__title {
  font-size: clamp(26px, 3.6vw, 42px);
  color: var(--ink);
}

.section__lead {
  max-width: 62ch;
  margin-top: 18px;
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 1.85;
  color: var(--slate);
}

.section--dark .section__title,
.section--deep .section__title { color: var(--white); }

.section--dark .section__lead,
.section--deep .section__lead { color: rgba(244, 247, 246, .72); }

.section--dark .section__eyebrow,
.section--deep .section__eyebrow { color: var(--amber); }

/* ---------- 10. Split skeleton ---------- */
.split {
  display: grid;
  gap: 40px;
  align-items: start;
}

.split--38-62 { grid-template-columns: minmax(0, 38fr) minmax(0, 62fr); }
.split--62-38 { grid-template-columns: minmax(0, 62fr) minmax(0, 38fr); }

.split__aside {
  position: sticky;
  top: calc(var(--header-h) + 28px);
  min-width: 0;
}

.split__main { min-width: 0; }

/* ---------- 11. Grid ---------- */
.grid {
  display: grid;
  gap: 24px;
}

.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }

/* ---------- 12. Rule index ---------- */
.rule-list {
  display: grid;
  border-top: 1px solid var(--line);
}

.rule-item {
  display: grid;
  grid-template-columns: 66px minmax(0, 1fr);
  gap: 0 20px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
}

.rule-item__no {
  padding-top: 4px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--sky);
}

.rule-item__title {
  font-family: var(--font-sans);
  font-size: 19px;
  font-weight: 700;
  letter-spacing: .01em;
  color: var(--ink);
}

.rule-item__text {
  max-width: 66ch;
  margin-top: 8px;
  font-family: var(--font-serif);
  font-size: 16px;
  line-height: 1.8;
  color: var(--slate);
}

.rule-item__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.section--dark .rule-list,
.section--deep .rule-list { border-top-color: rgba(201, 214, 216, .2); }

.section--dark .rule-item,
.section--deep .rule-item { border-bottom-color: rgba(201, 214, 216, .2); }

.section--dark .rule-item__title,
.section--deep .rule-item__title { color: var(--white); }

.section--dark .rule-item__text,
.section--deep .rule-item__text { color: rgba(244, 247, 246, .72); }

.section--dark .rule-item__no,
.section--deep .rule-item__no { color: var(--amber); }

/* ---------- 13. Tags ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  padding: 3px 11px;
  border: 1px solid var(--line);
  border-radius: var(--r-pill);
  background: rgba(201, 214, 216, .18);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .08em;
  line-height: 1.6;
  color: var(--slate);
  white-space: nowrap;
}

.tag--sky {
  border-color: rgba(30, 122, 140, .4);
  background: rgba(30, 122, 140, .09);
  color: var(--sky);
}

.tag--amber {
  border-color: rgba(232, 163, 61, .5);
  background: rgba(232, 163, 61, .13);
  color: var(--amber-deep);
}

.section--dark .tag,
.section--deep .tag {
  border-color: rgba(201, 214, 216, .28);
  background: rgba(201, 214, 216, .08);
  color: rgba(244, 247, 246, .74);
}

/* ---------- 14. Prose ---------- */
.prose {
  max-width: 70ch;
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 1.85;
  color: var(--ink);
}

.prose > p { margin-bottom: 1.15em; }

.prose h2 {
  margin: 2.2em 0 .65em;
  font-size: clamp(21px, 2.6vw, 30px);
}

.prose h3 {
  margin: 1.8em 0 .6em;
  font-size: 19px;
}

.prose h2:first-child,
.prose h3:first-child { margin-top: 0; }

.prose ul,
.prose ol {
  display: grid;
  gap: 8px;
  margin-bottom: 1.2em;
}

.prose li {
  position: relative;
  padding-left: 20px;
}

.prose li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: .78em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--sky);
}

.section--dark .prose,
.section--deep .prose { color: rgba(244, 247, 246, .82); }

.section--dark .prose li::before,
.section--deep .prose li::before { background: var(--amber); }

/* ---------- 15. Divider ---------- */
.divider {
  height: 1px;
  border: 0;
  background: var(--line);
}

.section--dark .divider,
.section--deep .divider { background: rgba(201, 214, 216, .22); }

/* ---------- 16. Breadcrumbs ---------- */
.crumbs {
  padding: 22px 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .06em;
  color: var(--slate);
}

.crumbs__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.crumbs__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--ink);
}

.crumbs__link {
  color: var(--sky);
  transition: color 160ms linear;
}

.crumbs__link:hover {
  color: var(--terra);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.crumbs__sep {
  color: var(--line);
}

/* ---------- 17. Disclosure ---------- */
.disclosure { border-bottom: 1px solid var(--line); }

.disclosure__head {
  display: flex;
  align-items: center;
  gap: 16px;
  width: 100%;
  padding: 20px 0;
  text-align: left;
}

.disclosure__title {
  flex: 1 1 auto;
  font-family: var(--font-sans);
  font-size: 17.5px;
  font-weight: 700;
  letter-spacing: .01em;
  line-height: 1.45;
  color: var(--ink);
  transition: color 160ms linear;
}

.disclosure__head:hover .disclosure__title { color: var(--sky); }

.disclosure__icon {
  position: relative;
  flex: 0 0 auto;
  width: 22px;
  height: 22px;
  border: 1px solid var(--line);
  border-radius: 50%;
  color: var(--sky);
  transition: background-color 180ms linear, border-color 180ms linear, color 180ms linear;
}

.disclosure__icon::before,
.disclosure__icon::after {
  content: "";
  position: absolute;
  left: 5px;
  right: 5px;
  top: 50%;
  height: 1.5px;
  background: currentColor;
  transform: translateY(-50%);
}

.disclosure__icon::after {
  transform: translateY(-50%) rotate(90deg);
  transition: transform 200ms linear, opacity 200ms linear;
}

.disclosure__head[aria-expanded="true"] .disclosure__icon {
  background: var(--sky);
  border-color: var(--sky);
  color: var(--white);
}

.disclosure__head[aria-expanded="true"] .disclosure__icon::after {
  transform: translateY(-50%) rotate(0deg);
  opacity: 0;
}

.disclosure__panel {
  height: 0;
  overflow: hidden;
  transition: height 240ms linear;
}

.disclosure__inner {
  max-width: 70ch;
  padding: 0 0 24px;
  font-family: var(--font-serif);
  font-size: 16px;
  line-height: 1.85;
  color: var(--slate);
}

.section--dark .disclosure,
.section--deep .disclosure { border-bottom-color: rgba(201, 214, 216, .2); }

.section--dark .disclosure__title,
.section--deep .disclosure__title { color: var(--white); }

.section--dark .disclosure__inner,
.section--deep .disclosure__inner { color: rgba(244, 247, 246, .72); }

/* ---------- 18. Data table ---------- */
.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--white);
  box-shadow: var(--shadow-soft);
}

.data-table {
  width: 100%;
  min-width: 640px;
  font-family: var(--font-serif);
  font-size: 15px;
}

.data-table caption {
  padding: 16px 20px 0;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--slate);
}

.data-table th {
  padding: 14px 20px;
  background: var(--deep);
  color: var(--white);
  font-family: var(--font-sans);
  font-size: 14.5px;
  font-weight: 700;
  letter-spacing: .04em;
  text-align: left;
}

.data-table td {
  padding: 14px 20px;
  border-top: 1px solid var(--line);
  line-height: 1.75;
  vertical-align: top;
}

.data-table tbody tr:nth-child(even) { background: rgba(201, 214, 216, .16); }

.data-table th:first-child,
.data-table td:first-child { white-space: nowrap; }

/* ---------- 19. Notice ---------- */
.notice {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 16px;
  padding: 20px 24px;
  border: 1px solid rgba(232, 163, 61, .42);
  border-radius: var(--r-lg);
  background: rgba(232, 163, 61, .1);
}

.notice__label {
  padding-top: 3px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--amber-deep);
  white-space: nowrap;
}

.notice p {
  font-family: var(--font-serif);
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--ink);
}

/* ---------- 20. Image frame ---------- */
.img-frame {
  position: relative;
  overflow: hidden;
  border-radius: var(--r-xl);
  background: linear-gradient(158deg, var(--deep) 0%, var(--ink) 58%, #0A1417 100%);
}

.img-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  opacity: .85;
  background-image:
    repeating-linear-gradient(115deg, rgba(30, 122, 140, .22) 0 1px, transparent 1px 28px),
    radial-gradient(120% 90% at 82% 6%, rgba(232, 163, 61, .18), transparent 56%);
}

.img-frame__inner {
  position: relative;
  z-index: 2;
  display: flex;
  align-items: flex-end;
  aspect-ratio: 16 / 10;
  padding: 22px;
}

.img-frame__media {
  position: absolute;
  inset: 0;
  z-index: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.img-frame__caption {
  position: relative;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  line-height: 1.7;
  color: rgba(244, 247, 246, .84);
}

.img-frame--wide .img-frame__inner { aspect-ratio: 21 / 9; }
.img-frame--tall .img-frame__inner { aspect-ratio: 3 / 4; }
.img-frame--soft { border-radius: var(--r-lg); }

/* ---------- 21. Reveal ---------- */
.reveal {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 200ms linear, transform 200ms linear;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

/* ---------- 22. Back to top ---------- */
.to-top {
  position: fixed;
  right: 22px;
  bottom: 22px;
  z-index: 70;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  border: 1px solid rgba(201, 214, 216, .3);
  border-radius: 50%;
  background: var(--deep);
  color: var(--white);
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity 200ms linear, transform 200ms linear, visibility 0s linear 200ms, background-color 180ms linear;
}

.to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: none;
  transition-delay: 0s;
}

.to-top:hover { background: var(--sky); }

/* ---------- 23. Site footer ---------- */
.site-footer {
  position: relative;
  overflow: hidden;
  margin-top: 96px;
  background: var(--ink);
  color: rgba(244, 247, 246, .78);
  font-family: var(--font-sans);
}

.footer__contour {
  position: absolute;
  inset: auto 0 0 0;
  height: 340px;
  pointer-events: none;
  opacity: .55;
  background-image:
    repeating-radial-gradient(120% 82% at 12% 122%, rgba(30, 122, 140, .24) 0 1px, transparent 1px 46px),
    repeating-radial-gradient(120% 82% at 88% 132%, rgba(21, 156, 140, .18) 0 1px, transparent 1px 62px);
  -webkit-mask-image: linear-gradient(180deg, transparent 0%, #000 72%);
  mask-image: linear-gradient(180deg, transparent 0%, #000 72%);
}

.footer__inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 38fr) minmax(0, 62fr);
  gap: 56px;
  padding-top: 88px;
  padding-bottom: 56px;
}

.footer__lead { max-width: 40ch; }

.footer__brand {
  font-family: var(--font-sans);
  font-size: 26px;
  font-weight: 800;
  letter-spacing: .02em;
  color: var(--white);
}

.footer__tagline {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .16em;
  color: var(--amber);
}

.footer__note {
  margin-top: 18px;
  font-family: var(--font-serif);
  font-size: 15px;
  line-height: 1.85;
  color: rgba(244, 247, 246, .72);
}

.footer__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.footer__grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 32px;
}

.footer__col-title {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding-bottom: 12px;
  border-bottom: 1px solid rgba(201, 214, 216, .2);
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .08em;
  color: var(--white);
}

.footer__col-index {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--sky);
}

.footer__list {
  display: grid;
  gap: 9px;
  margin-top: 14px;
}

.footer__link {
  font-size: 15px;
  line-height: 1.7;
  color: rgba(244, 247, 246, .76);
  transition: color 160ms linear;
}

.footer__link:hover {
  color: var(--white);
  text-decoration: underline;
  text-decoration-color: var(--sky);
  text-underline-offset: 4px;
}

.footer__item {
  font-family: var(--font-mono);
  font-size: 13.5px;
  line-height: 1.75;
  color: rgba(244, 247, 246, .76);
  word-break: break-word;
}

.footer__base {
  position: relative;
  z-index: 1;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 26px;
  padding-top: 22px;
  padding-bottom: 34px;
  border-top: 1px solid rgba(201, 214, 216, .16);
}

.footer__icp {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .04em;
  color: rgba(244, 247, 246, .6);
}

.footer__meta {
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.7;
  color: rgba(244, 247, 246, .52);
}

/* ---------- 24. Responsive ---------- */
@media (max-width: 1180px) {
  .brand__tagline { display: none; }
  .nav { gap: 14px; }
  .nav__link { padding: 9px 10px; font-size: 14.5px; }
}

@media (max-width: 1024px) {
  .nav__utility { display: none; }
  .split,
  .split--38-62,
  .split--62-38 { grid-template-columns: minmax(0, 1fr); gap: 32px; }
  .split__aside { position: static; }
}

@media (max-width: 899px) {
  :root { --header-h: 64px; --step: 72px; }

  .nav__toggle { display: inline-flex; }

  .nav {
    position: fixed;
    left: 0;
    right: 0;
    top: var(--header-h);
    display: block;
    max-height: calc(100vh - var(--header-h));
    margin-left: 0;
    padding: 18px var(--gutter) 26px;
    overflow-y: auto;
    background: var(--ink);
    border-top: 1px solid rgba(201, 214, 216, .18);
    box-shadow: 0 26px 50px -30px rgba(0, 0, 0, .9);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity 200ms linear, transform 200ms linear, visibility 0s linear 200ms;
  }

  .site-header[data-open] .nav {
    opacity: 1;
    visibility: visible;
    transform: none;
    transition-delay: 0s;
  }

  .nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
  }

  .nav__link {
    display: block;
    padding: 13px 14px;
    font-size: 17px;
    border-radius: var(--r-md);
  }

  .nav__link[aria-current="page"] { background: rgba(30, 122, 140, .2); }

  .nav__link[aria-current="page"]::after {
    left: 14px;
    right: auto;
    width: 18px;
    bottom: 7px;
  }

  .grid--2,
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }

  .footer__inner { grid-template-columns: minmax(0, 1fr); gap: 42px; }
  .footer__lead { max-width: none; }
}

@media (max-width: 640px) {
  body { font-size: 16.5px; }

  .brand__text { font-size: 17px; }
  .version-badge { padding: 4px 10px; font-size: 11px; letter-spacing: .02em; }
  .nav__toggle { padding: 8px 12px; }
  .nav__toggle-text { display: none; }

  .grid--2,
  .grid--3 { grid-template-columns: minmax(0, 1fr); }

  .rule-item {
    grid-template-columns: minmax(0, 1fr);
    gap: 6px;
    padding: 20px 0;
  }

  .rule-item__no { padding-top: 0; }

  .footer__grid { grid-template-columns: minmax(0, 1fr); gap: 28px; }
  .footer__inner { padding-top: 64px; padding-bottom: 40px; }
  .footer__base { flex-direction: column; align-items: flex-start; }

  .notice { grid-template-columns: minmax(0, 1fr); gap: 8px; }

  .to-top { right: 16px; bottom: 16px; }
}

/* ---------- 25. Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    transition-duration: .001ms !important;
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
  }

  .reveal { opacity: 1; transform: none; }
  .to-top { transform: none; }
  .scroll-progress { transition: none; }
}