/* ===================================================================
   金博游艺 · 共享样式 /assets/site.css
   暖金深墨 · 目录型内容地图 · 现代粗野主义展签语言
   =================================================================== */

/* ---------- 1. 设计令牌 ---------- */
:root {
  --ink: #11100E;
  --ink-soft: #1B1814;
  --gold: #D6A84B;
  --champagne: #F1D9A6;
  --paper: #F6F0E4;
  --paper-2: #EDE4D2;
  --paper-raised: #FFFCF5;
  --amber: #C96A2B;
  --celadon: #4F7C6D;
  --smoke: #3A342C;
  --copper: #8C6A3F;
  --alert: #A33A2B;

  --font-serif: "Songti SC", "Source Han Serif SC", "Noto Serif SC", "SimSun", Georgia, "Times New Roman", serif;
  --font-sans: "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC", "Noto Sans SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

  --wrap: 1240px;
  --gutter: clamp(16px, 4vw, 40px);

  --line: 2px;
  --shadow-hard: 6px 6px 0 rgba(17, 16, 14, 0.16);
  --shadow-gold: 6px 6px 0 rgba(214, 168, 75, 0.48);

  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ---------- 2. Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.7;
  color: var(--ink-soft);
  background-color: var(--paper);
  background-image: radial-gradient(rgba(58, 52, 44, 0.055) 1px, transparent 1px);
  background-size: 22px 22px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd, hr { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img, svg, video { max-width: 100%; height: auto; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
a { color: inherit; text-decoration: none; }
table { border-collapse: collapse; width: 100%; }
main { display: block; }

:focus-visible {
  outline: 3px solid var(--gold);
  outline-offset: 3px;
}

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

#main-content { scroll-margin-top: 110px; }

/* ---------- 3. 中文排版层级 ---------- */
.display {
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: clamp(3rem, 9vw, 8.25rem);
  line-height: 0.94;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

.title-xl {
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: clamp(2.25rem, 5vw, 3.5rem);
  line-height: 1.08;
  letter-spacing: -0.01em;
  text-wrap: balance;
}

.title-lg {
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: clamp(1.75rem, 3.4vw, 2.75rem);
  line-height: 1.14;
  text-wrap: balance;
}

.title-md {
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: clamp(1.25rem, 2.2vw, 1.75rem);
  line-height: 1.28;
}

.lede {
  font-size: clamp(1rem, 1.4vw, 1.125rem);
  line-height: 1.78;
  color: var(--smoke);
  max-width: 64ch;
}

.kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--copper);
}

.kicker::before {
  content: "";
  width: 28px;
  height: 2px;
  background: var(--gold);
}

.prose a {
  color: var(--copper);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
  transition: color 0.18s var(--ease);
}
.prose a:hover { color: var(--amber); }

/* ---------- 4. 布局容器 ---------- */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.wrap--narrow { max-width: 860px; }

.section { padding-block: clamp(40px, 7vw, 88px); }
.section--ink { background: var(--ink); color: var(--paper); }
.section--paper { background: var(--paper-2); }
.section--ink .lede { color: rgba(246, 240, 228, 0.74); }
.section--ink .kicker { color: var(--gold); }

.grid { display: grid; gap: clamp(16px, 2.4vw, 28px); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.grid--split { grid-template-columns: minmax(0, 3fr) minmax(0, 7fr); }
.grid--split-r { grid-template-columns: minmax(0, 7fr) minmax(0, 3fr); }

.rule {
  height: 2px;
  border: 0;
  margin: 0;
  background: linear-gradient(90deg, var(--gold), rgba(214, 168, 75, 0));
}

/* ---------- 5. 通用按钮 ---------- */
.btn {
  --btn-bg: var(--gold);
  --btn-fg: var(--ink);
  --btn-bd: var(--ink);
  --btn-sh: rgba(17, 16, 14, 0.85);

  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 13px 22px;
  background: var(--btn-bg);
  color: var(--btn-fg);
  border: 2px solid var(--btn-bd);
  box-shadow: 4px 4px 0 var(--btn-sh);
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 15px;
  line-height: 1.2;
  letter-spacing: 0.05em;
  text-decoration: none;
  cursor: pointer;
  transition: transform 0.18s var(--ease), box-shadow 0.18s var(--ease),
              background-color 0.18s var(--ease), color 0.18s var(--ease),
              border-color 0.18s var(--ease);
}

.btn:hover {
  transform: translate(-2px, -2px);
  box-shadow: 6px 6px 0 var(--btn-sh);
  background: var(--champagne);
}

.btn:active {
  transform: translate(2px, 2px);
  box-shadow: 1px 1px 0 var(--btn-sh);
}

.btn--gold {
  --btn-bg: var(--gold);
  --btn-fg: var(--ink);
}

.btn--ink {
  --btn-bg: var(--ink);
  --btn-fg: var(--paper);
  --btn-bd: var(--ink);
  --btn-sh: rgba(17, 16, 14, 0.4);
}
.btn--ink:hover { background: var(--smoke); color: var(--paper); }

.btn--ghost {
  --btn-bg: transparent;
  --btn-fg: var(--champagne);
  --btn-bd: var(--gold);
  --btn-sh: rgba(214, 168, 75, 0.35);
}
.btn--ghost:hover { background: var(--gold); color: var(--ink); }

.btn--sm {
  padding: 9px 15px;
  font-size: 13.5px;
  box-shadow: 3px 3px 0 var(--btn-sh);
}
.btn--sm:hover { box-shadow: 4px 4px 0 var(--btn-sh); }

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

/* ---------- 6. 跳转链接 ---------- */
.skip-link {
  position: absolute;
  top: -80px;
  left: 16px;
  z-index: 200;
  padding: 10px 18px;
  background: var(--gold);
  color: var(--ink);
  font-weight: 700;
  font-size: 14px;
  letter-spacing: 0.06em;
  border: 2px solid var(--ink);
  box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.5);
  transition: top 0.18s var(--ease);
}

.skip-link:focus {
  top: 14px;
}

/* ---------- 7. 页头：紧凑命令栏 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 90;
  isolation: isolate;
  background: var(--ink);
  color: var(--paper);
  border-bottom: 3px solid var(--gold);
  transition: box-shadow 0.2s var(--ease);
}

.site-header::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background: radial-gradient(90% 170% at 82% -30%, rgba(214, 168, 75, 0.2), transparent 62%);
}

.site-header[data-scrolled] {
  box-shadow: 0 16px 34px -20px rgba(0, 0, 0, 0.9);
}

.header__top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 8px var(--gutter);
  border-bottom: 1px solid rgba(214, 168, 75, 0.22);
}

.header__kicker {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(246, 240, 228, 0.6);
}

.header__version {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 3px 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--champagne);
  border: 1px solid rgba(214, 168, 75, 0.42);
  transition: background-color 0.18s var(--ease), color 0.18s var(--ease),
              border-color 0.18s var(--ease);
}

.header__version::before {
  content: "";
  width: 6px;
  height: 6px;
  background: var(--celadon);
  box-shadow: 0 0 0 3px rgba(79, 124, 109, 0.28);
}

.header__version:hover {
  background: var(--gold);
  color: var(--ink);
  border-color: var(--gold);
}

.header__bar {
  position: relative;
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 28px);
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 12px var(--gutter) 14px;
}

/* 品牌铜牌 */
.brand {
  flex: 0 0 auto;
  margin-right: auto;
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: inherit;
  text-decoration: none;
}

.brand__mark {
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: 23px;
  line-height: 1;
  color: var(--ink);
  background: linear-gradient(148deg, var(--champagne), var(--gold) 52%, var(--copper));
  border: 2px solid var(--gold);
  clip-path: polygon(0 0, 100% 0, 100% 70%, 70% 100%, 0 100%);
  transition: transform 0.18s var(--ease);
}

.brand:hover .brand__mark { transform: translateY(-2px); }

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.brand__name {
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: 20px;
  letter-spacing: 0.08em;
  color: var(--paper);
}

.brand__sub {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--gold);
}

/* 主导航 */
.nav {
  flex: 0 1 auto;
}

.nav__list {
  display: flex;
  align-items: center;
  gap: clamp(2px, 0.8vw, 12px);
}

.nav__link {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  padding: 9px 10px;
  font-size: 15px;
  letter-spacing: 0.04em;
  color: rgba(246, 240, 228, 0.78);
  border-bottom: 2px solid transparent;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.nav__link::after {
  content: "";
  position: absolute;
  left: 10px;
  right: 10px;
  bottom: 1px;
  height: 2px;
  background: var(--gold);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.22s var(--ease);
}

.nav__num {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.1em;
  color: var(--copper);
  transition: color 0.18s var(--ease);
}

.nav__link:hover,
.nav__link:focus-visible { color: var(--champagne); }

.nav__link:hover::after,
.nav__link:focus-visible::after,
.nav__link[aria-current="page"]::after { transform: scaleX(1); }

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

.header__actions {
  flex: 0 0 auto;
  margin-left: clamp(8px, 1.5vw, 24px);
  display: flex;
  align-items: center;
  gap: 10px;
}

/* 目录开关 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  background: rgba(214, 168, 75, 0.08);
  border: 2px solid var(--gold);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  transition: background-color 0.18s var(--ease), color 0.18s var(--ease);
}

.nav-toggle:hover { background: var(--gold); color: var(--ink); }

.nav-toggle__bars {
  display: grid;
  gap: 4px;
  width: 18px;
}

.nav-toggle__bars i {
  display: block;
  height: 2px;
  background: currentColor;
  transition: transform 0.2s var(--ease), opacity 0.2s var(--ease);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(2) {
  opacity: 0;
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

/* 滚动进度轨 */
.header__progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -3px;
  height: 3px;
  background: rgba(214, 168, 75, 0.16);
  pointer-events: none;
}

.header__progress span {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--copper), var(--gold) 55%, var(--champagne));
}

/* ---------- 8. 页脚：说明墙 ---------- */
.site-footer {
  position: relative;
  background: var(--ink);
  color: rgba(246, 240, 228, 0.7);
  border-top: 3px solid var(--gold);
  padding-top: clamp(36px, 6vw, 64px);
  font-size: 15px;
  overflow: hidden;
}

.site-footer::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 240px;
  pointer-events: none;
  background: radial-gradient(72% 100% at 16% 0%, rgba(214, 168, 75, 0.18), transparent 70%);
}

.footer__inner {
  position: relative;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.footer__grid {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) repeat(4, minmax(0, 1fr));
  gap: clamp(24px, 3vw, 44px);
}

.brand--footer { margin-right: 0; }

.footer__pitch {
  margin-top: 16px;
  max-width: 34ch;
  font-size: 14px;
  line-height: 1.78;
  color: rgba(246, 240, 228, 0.55);
}

.footer__title {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 14px;
  padding-bottom: 10px;
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: 15px;
  letter-spacing: 0.08em;
  color: var(--paper);
  border-bottom: 1px solid rgba(214, 168, 75, 0.24);
}

.footer__num {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 400;
  letter-spacing: 0.1em;
  color: var(--gold);
}

.footer__list { display: grid; gap: 8px; }

.footer__link {
  position: relative;
  display: inline-block;
  padding-block: 2px;
  font-size: 14px;
  color: rgba(246, 240, 228, 0.68);
  transition: color 0.18s var(--ease), transform 0.18s var(--ease);
}

.footer__link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 1px;
  background: var(--gold);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.22s var(--ease);
}

.footer__link:hover {
  color: var(--champagne);
  transform: translateX(2px);
}
.footer__link:hover::after { transform: scaleX(1); }

.footer__contact {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  justify-content: space-between;
  gap: 20px 40px;
  margin-top: clamp(28px, 4vw, 48px);
  padding: 24px 0;
  border-top: 2px solid rgba(214, 168, 75, 0.24);
  border-bottom: 2px solid rgba(214, 168, 75, 0.24);
}

.footer__contact-item {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.footer__contact-key {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--gold);
}

.footer__contact-val {
  font-size: 16px;
  letter-spacing: 0.02em;
  color: var(--paper);
}

.footer__contact-item--cta { gap: 8px; }

.footer__note {
  flex-basis: 100%;
  max-width: 78ch;
  font-size: 13px;
  line-height: 1.7;
  color: rgba(246, 240, 228, 0.48);
}

.footer__legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 24px;
  padding: 20px 0 28px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: rgba(246, 240, 228, 0.45);
}

.footer__legal-links {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
}

.footer__legal-links a {
  color: rgba(246, 240, 228, 0.6);
  border-bottom: 1px solid transparent;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.footer__legal-links a:hover {
  color: var(--gold);
  border-color: var(--gold);
}

/* ---------- 9. 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--copper);
}

.breadcrumb a {
  color: var(--copper);
  border-bottom: 1px solid transparent;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.breadcrumb a:hover {
  color: var(--ink);
  border-color: var(--gold);
}

.breadcrumb__sep { color: var(--gold); }
.breadcrumb [aria-current="page"] { color: var(--smoke); }

/* ---------- 10. 展签 / 标签 / 卡片 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  border: 1px solid currentColor;
}

.tag--gold { color: var(--gold); background: rgba(214, 168, 75, 0.1); }
.tag--amber { color: var(--amber); background: rgba(201, 106, 43, 0.1); }
.tag--celadon { color: var(--celadon); background: rgba(79, 124, 109, 0.12); }

.card {
  position: relative;
  background: var(--paper-raised);
  border: 2px solid var(--ink);
  box-shadow: var(--shadow-hard);
  padding: clamp(18px, 2.4vw, 28px);
  transition: transform 0.2s var(--ease), box-shadow 0.2s var(--ease),
              border-color 0.2s var(--ease);
}

.card:hover,
.card:focus-within {
  transform: translate(-2px, -2px);
  box-shadow: var(--shadow-gold);
  border-color: var(--copper);
}

.card__num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--copper);
}

.section--ink .card {
  background: rgba(246, 240, 228, 0.05);
  border-color: var(--copper);
  color: var(--paper);
  box-shadow: 6px 6px 0 rgba(0, 0, 0, 0.5);
}

.section--ink .card:hover {
  border-color: var(--gold);
  box-shadow: 6px 6px 0 rgba(214, 168, 75, 0.45);
}

/* ---------- 11. 侧边索引 ---------- */
.index {
  display: grid;
  gap: 2px;
}

.index__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 9px 12px;
  font-size: 14px;
  line-height: 1.5;
  color: var(--smoke);
  text-decoration: none;
  border-left: 2px solid rgba(58, 52, 44, 0.2);
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease),
              background-color 0.18s var(--ease), transform 0.18s var(--ease);
}

.index__link:hover {
  color: var(--ink);
  background: rgba(214, 168, 75, 0.14);
  border-left-color: var(--gold);
  transform: translateX(2px);
}

.index__link.is-current {
  color: var(--ink);
  font-weight: 600;
  background: rgba(214, 168, 75, 0.2);
  border-left-color: var(--gold);
}

.index__num {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--copper);
}

/* ---------- 12. 图片容器基础（供页面阶段放置占位） ---------- */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  background:
    radial-gradient(120% 130% at 18% 0%, rgba(214, 168, 75, 0.34), transparent 58%),
    linear-gradient(150deg, #241F16, var(--ink) 62%, #0B0A08);
  border: 2px solid var(--smoke);
  box-shadow: 6px 6px 0 rgba(17, 16, 14, 0.22);
}

.media-frame::after {
  content: "";
  position: absolute;
  inset: auto -10% -40% 40%;
  height: 70%;
  background: radial-gradient(closest-side, rgba(241, 217, 166, 0.22), transparent);
  pointer-events: none;
}

.media-frame > img,
.media-frame > svg,
.media-frame > .media-frame__img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media-frame--square { aspect-ratio: 1 / 1; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame--wide { aspect-ratio: 21 / 9; }

.media-frame__tag {
  position: absolute;
  left: 0;
  bottom: 0;
  z-index: 2;
  padding: 6px 12px;
  background: var(--ink);
  color: var(--gold);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  border-top: 2px solid var(--gold);
  border-right: 2px solid var(--gold);
}

/* ---------- 13. 渐显 ---------- */
.js [data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.55s var(--ease), transform 0.55s var(--ease);
}

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

/* ---------- 14. 响应式 ---------- */
@media (max-width: 1080px) {
  .nav-toggle { display: inline-flex; }

  .nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: none;
    margin-left: 0;
    padding: 10px var(--gutter) 22px;
    background: linear-gradient(180deg, #191710, var(--ink) 55%);
    border-bottom: 3px solid var(--gold);
    box-shadow: 0 28px 50px rgba(0, 0, 0, 0.6);
    max-height: calc(100vh - 130px);
    overflow-y: auto;
  }

  .nav[data-open] { display: block; }

  .nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .nav__item + .nav__item { border-top: 1px solid rgba(214, 168, 75, 0.16); }

  .nav__link {
    width: 100%;
    padding: 16px 4px;
    font-size: 17px;
    border-bottom: 0;
  }

  .nav__link::after {
    left: 4px;
    right: auto;
    bottom: 11px;
    width: 24px;
  }

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

  .footer__brand {
    grid-column: 1 / -1;
    max-width: none;
  }
}

@media (max-width: 900px) {
  .grid--3,
  .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--split,
  .grid--split-r { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 640px) {
  body { font-size: 16px; }

  .header__kicker { font-size: 9px; letter-spacing: 0.14em; }
  .header__version { font-size: 9px; letter-spacing: 0.1em; padding: 2px 8px; }
  .header__bar { padding: 9px var(--gutter) 11px; gap: 10px; }
  .brand { gap: 10px; }
  .brand__mark { width: 38px; height: 38px; font-size: 19px; }
  .brand__name { font-size: 17px; }
  .brand__sub { font-size: 9px; letter-spacing: 0.16em; }
  .header__cta { display: none; }
  .header__actions { margin-left: auto; }

  .grid--2,
  .grid--3,
  .grid--4 { grid-template-columns: minmax(0, 1fr); }

  .footer__grid { grid-template-columns: minmax(0, 1fr); }
  .footer__contact { flex-direction: column; gap: 18px; }
  .footer__legal {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }
}

/* ---------- 15. 降低动效 ---------- */
@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;
  }

  .btn:hover,
  .card:hover,
  .card:focus-within,
  .footer__link:hover,
  .index__link:hover,
  .brand:hover .brand__mark {
    transform: none;
  }

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