/* ============================================================
   AB游艺中心 · 共享样式 /assets/site.css
   深海蓝夜场底色 × 复古刊物版面秩序
   ============================================================ */

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

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

body,
h1, h2, h3, h4, h5, h6,
p, ul, ol, li, figure, blockquote, dl, dd { margin: 0; }

ul, ol { padding: 0; list-style: none; }

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

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

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

/* ---------- 2. 设计变量 ---------- */
:root {
  --abyss: #071A2B;
  --night: #0C263B;
  --surface: #123A54;
  --surface-hi: #17445F;
  --cyan: #35E0D0;
  --cyan-soft: #8FF5EA;
  --coral: #FF6B4A;
  --sand: #F2C879;
  --cream: #F6EEDC;
  --ink: #1A120B;
  --mist: #B9CBD8;

  --rail: 84px;
  --wrap: 1160px;
  --gutter: clamp(18px, 4vw, 46px);

  --font-display: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-body: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", "PingFang SC", monospace;

  --r-s: 8px;
  --r-m: 14px;
  --r-l: 22px;
  --ease: cubic-bezier(.22, .61, .36, 1);
}

/* ---------- 3. 基础排版 ---------- */
body {
  margin: 0;
  padding-left: var(--rail);
  min-height: 100vh;
  overflow-x: hidden;
  font-family: var(--font-body);
  font-size: 16.5px;
  line-height: 1.75;
  color: var(--mist);
  background-color: var(--abyss);
  background-image:
    radial-gradient(1100px 620px at 78% -12%, rgba(53, 224, 208, .11), transparent 62%),
    radial-gradient(880px 520px at 2% 6%, rgba(255, 107, 74, .09), transparent 58%),
    radial-gradient(1200px 900px at 50% 112%, rgba(18, 58, 84, .8), transparent 72%);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: .04em;
  line-height: 1.25;
  color: var(--cream);
}

p, li { max-width: 64ch; }

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

:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 4. 跳转链接 ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: calc(var(--rail) + 10px);
  z-index: 300;
  padding: 10px 20px;
  border-radius: 999px;
  background: var(--cyan);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .08em;
  transform: translateY(-180%);
  transition: transform .24s var(--ease);
}
.skip-link:focus { transform: translateY(0); }

/* ---------- 5. 页头 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: linear-gradient(180deg, rgba(7, 26, 43, .97), rgba(7, 26, 43, .91));
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(53, 224, 208, .2);
  transition: box-shadow .28s var(--ease);
}
.site-header[data-compact] {
  box-shadow: 0 16px 34px -26px rgba(0, 0, 0, .95);
}

/* 左侧品牌轨道 */
.brand-rail {
  position: fixed;
  inset: 0 auto 0 0;
  width: var(--rail);
  z-index: 70;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
  padding: 22px 0 26px;
  background: linear-gradient(180deg, #0C263B 0%, #071A2B 46%, #0C263B 100%);
  border-right: 1px solid rgba(53, 224, 208, .18);
}
.brand-rail::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(120px 240px at 50% 12%, rgba(53, 224, 208, .18), transparent 72%),
    radial-gradient(140px 260px at 50% 92%, rgba(255, 107, 74, .14), transparent 72%);
}
.rail-mark {
  position: relative;
  z-index: 1;
  width: 12px;
  height: 12px;
  border-radius: 3px;
  background: var(--coral);
  box-shadow: 0 0 0 4px rgba(255, 107, 74, .16), 0 0 18px rgba(255, 107, 74, .55);
}
.rail-brand {
  position: relative;
  z-index: 1;
  writing-mode: vertical-rl;
  text-orientation: mixed;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 13px;
  letter-spacing: .44em;
  color: var(--sand);
}
.rail-ticks {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  gap: 7px;
}
.rail-ticks i {
  display: block;
  width: 16px;
  height: 2px;
  background: rgba(53, 224, 208, .42);
}
.rail-ticks i:nth-child(2) { width: 10px; background: rgba(242, 200, 121, .5); }
.rail-ticks i:nth-child(3) { width: 22px; background: rgba(53, 224, 208, .24); }
.rail-ticks i:nth-child(4) { width: 6px; background: rgba(255, 107, 74, .6); }

/* 阅读进度条 */
.read-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 3px;
  background: rgba(53, 224, 208, .1);
  pointer-events: none;
  overflow: hidden;
}
.read-progress__bar {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--cyan) 0%, var(--cyan-soft) 58%, var(--sand) 100%);
  box-shadow: 0 0 12px rgba(53, 224, 208, .55);
}

/* 刊头 */
.masthead {
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.masthead__bar {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 14px;
  padding-block: 15px 10px;
  transition: padding .28s var(--ease);
}
.site-header[data-compact] .masthead__bar { padding-block: 7px 5px; }

.masthead__tag {
  display: flex;
  flex-direction: column;
  gap: 1px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  line-height: 1.5;
  color: rgba(185, 203, 216, .62);
}
.masthead__tag-line { color: var(--sand); }
.masthead__tag-sub { letter-spacing: .22em; }

.brand-lockup {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  justify-self: center;
  border-radius: var(--r-m);
}
.brand-lockup__mark {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border-radius: 12px;
  background: linear-gradient(145deg, var(--coral), #D63E22);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .04em;
  box-shadow: 0 0 0 1px rgba(242, 200, 121, .4), 0 10px 22px -14px rgba(255, 107, 74, .95);
  transition: transform .24s var(--ease), box-shadow .24s var(--ease);
}
.brand-lockup:hover .brand-lockup__mark {
  transform: translateY(-1px) rotate(-3deg);
  box-shadow: 0 0 0 1px var(--sand), 0 14px 26px -14px rgba(255, 107, 74, 1);
}
.brand-lockup__text { display: block; }
.brand-line {
  display: block;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(19px, 2.1vw, 24px);
  letter-spacing: .14em;
  line-height: 1.2;
  color: var(--cream);
}
.brand-sub {
  display: block;
  margin-top: 2px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .13em;
  color: var(--sand);
  transition: opacity .22s var(--ease);
}
.site-header[data-compact] .brand-sub { display: none; }
.site-header[data-compact] .masthead__tag { display: none; }

.masthead__tools {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 8px;
}
.tool-link {
  padding: 7px 13px;
  border-radius: 999px;
  border: 1px solid rgba(53, 224, 208, .26);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--mist);
  transition: color .22s var(--ease), border-color .22s var(--ease), background .22s var(--ease);
}
.tool-link:hover {
  color: var(--cyan-soft);
  border-color: var(--cyan);
  background: rgba(53, 224, 208, .1);
}
.tool-link--accent {
  border-color: rgba(255, 107, 74, .5);
  color: var(--sand);
}
.tool-link--accent:hover {
  color: var(--coral);
  border-color: var(--coral);
  background: rgba(255, 107, 74, .12);
}

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 8px 13px;
  border-radius: 999px;
  border: 1px solid rgba(53, 224, 208, .34);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--cyan-soft);
  transition: border-color .22s var(--ease), background .22s var(--ease);
}
.nav-toggle:hover { border-color: var(--cyan); background: rgba(53, 224, 208, .12); }
.nav-toggle__bars { display: flex; flex-direction: column; gap: 3px; }
.nav-toggle__bars i {
  display: block;
  width: 16px;
  height: 2px;
  background: currentColor;
  transition: transform .24s var(--ease), opacity .2s var(--ease);
}
.site-header[data-open] .nav-toggle__bars i:nth-child(1) { transform: translateY(5px) rotate(45deg); }
.site-header[data-open] .nav-toggle__bars i:nth-child(2) { opacity: 0; }
.site-header[data-open] .nav-toggle__bars i:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

/* 主导航 */
.site-nav { border-top: 1px solid rgba(185, 203, 216, .13); }
.nav-list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: clamp(2px, 1vw, 16px);
  padding-block: 9px;
}
.nav-link {
  position: relative;
  display: inline-block;
  padding: 6px 10px;
  border-radius: var(--r-s);
  font-size: 15px;
  letter-spacing: .05em;
  color: var(--mist);
  transition: color .22s var(--ease);
}
.nav-link::after {
  content: "";
  position: absolute;
  left: 10px;
  right: 10px;
  bottom: 2px;
  height: 2px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform .26s var(--ease);
}
.nav-link:hover { color: var(--cream); }
.nav-link:hover::after { transform: scaleX(1); }
.nav-link[aria-current="page"] { color: var(--cyan); }
.nav-link[aria-current="page"]::after {
  transform: scaleX(1);
  background: var(--sand);
}

/* 常用入口磁贴 */
.tile-strip {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 8px;
  padding-bottom: 14px;
}
.tile {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 11px;
  border-radius: 10px;
  background: var(--surface);
  border: 1px solid rgba(53, 224, 208, .16);
  font-size: 13px;
  letter-spacing: .02em;
  color: var(--mist);
  transition: transform .24s var(--ease), background .24s var(--ease),
              border-color .24s var(--ease), color .24s var(--ease),
              box-shadow .24s var(--ease);
}
.tile:hover {
  transform: translateY(-2px);
  background: var(--surface-hi);
  border-color: var(--cyan);
  color: var(--cream);
  box-shadow: 0 0 0 1px rgba(53, 224, 208, .35), 0 12px 24px -18px rgba(53, 224, 208, .9);
}
.tile__no {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .08em;
  color: var(--sand);
  transition: color .24s var(--ease);
}
.tile:hover .tile__no { color: var(--cyan-soft); }
.tile__label { min-width: 0; }

/* ---------- 6. 页脚 ---------- */
.site-footer {
  margin-top: clamp(56px, 9vw, 110px);
  background: linear-gradient(180deg, #0C263B 0%, #061420 62%, #050F19 100%);
  border-top: 1px solid rgba(53, 224, 208, .22);
  color: var(--mist);
}
.footer-inner {
  max-width: var(--wrap);
  margin-inline: auto;
  padding: clamp(34px, 5vw, 62px) var(--gutter) 26px;
}
.footer-top {
  display: grid;
  grid-template-columns: minmax(200px, .9fr) 2fr;
  gap: clamp(26px, 4vw, 58px);
  padding-bottom: clamp(26px, 3.6vw, 42px);
}
.footer-brand { display: flex; flex-direction: column; gap: 10px; }
.footer-brand__mark {
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border-radius: 13px;
  background: linear-gradient(145deg, var(--coral), #C9381E);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .04em;
  box-shadow: 0 0 0 1px rgba(242, 200, 121, .35), 0 0 26px -8px rgba(255, 107, 74, .7);
}
.footer-brand__name {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 19px;
  letter-spacing: .12em;
  color: var(--cream);
}
.footer-brand__desc {
  font-size: 14px;
  line-height: 1.7;
  color: rgba(185, 203, 216, .78);
  max-width: 26ch;
}
.footer-nav {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(18px, 3vw, 34px);
}
.footer-col { display: flex; flex-direction: column; gap: 12px; }
.footer-col__title {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .2em;
  color: var(--sand);
  padding-bottom: 8px;
  border-bottom: 1px solid rgba(53, 224, 208, .22);
}
.footer-links { display: flex; flex-direction: column; gap: 8px; }
.footer-link {
  display: inline-block;
  font-size: 14.5px;
  color: var(--mist);
  transition: color .22s var(--ease), transform .22s var(--ease);
}
.footer-link:hover {
  color: var(--cyan-soft);
  transform: translateX(3px);
}
.footer-contact {
  display: flex;
  flex-wrap: wrap;
  gap: 10px clamp(20px, 4vw, 44px);
  padding-block: clamp(18px, 2.6vw, 26px);
  border-top: 1px solid rgba(185, 203, 216, .14);
  border-bottom: 1px solid rgba(185, 203, 216, .14);
}
.footer-contact__item {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .02em;
  max-width: none;
}
.footer-contact__key {
  font-size: 11px;
  letter-spacing: .16em;
  color: rgba(242, 200, 121, .8);
}
.footer-contact__val { color: var(--mist); }
.footer-base {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px 20px;
  padding-top: 20px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: rgba(185, 203, 216, .62);
}
.footer-base__copy,
.footer-base__icp { max-width: none; }

/* ---------- 7. 版式工具 ---------- */
.wrap {
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.wrap--narrow { max-width: 780px; }

.section { padding-block: clamp(38px, 6vw, 82px); }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .17em;
  color: var(--sand);
}
.eyebrow::before {
  content: "";
  width: 22px;
  height: 1px;
  background: var(--sand);
}

.section-title {
  font-size: clamp(25px, 3.4vw, 34px);
  letter-spacing: .05em;
}

.lede {
  font-size: clamp(15.5px, 1.7vw, 18px);
  line-height: 1.78;
  color: var(--mist);
}

.label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--sand);
}

.note {
  font-size: 13.5px;
  line-height: 1.7;
  color: rgba(185, 203, 216, .72);
  max-width: 60ch;
}

.divider {
  height: 1px;
  border: 0;
  margin: 0;
  background: linear-gradient(90deg, rgba(53, 224, 208, .5), rgba(242, 200, 121, .26), transparent);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* ---------- 8. 栅格 ---------- */
.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)); }

/* ---------- 9. 卡片与嵌块 ---------- */
.card {
  position: relative;
  padding: clamp(18px, 2.4vw, 28px);
  border-radius: var(--r-m);
  background: var(--night);
  border: 1px solid rgba(53, 224, 208, .15);
  color: var(--mist);
  transition: border-color .24s var(--ease), transform .24s var(--ease);
}
.card:hover { border-color: rgba(53, 224, 208, .42); }
.card--cream {
  background: var(--cream);
  color: var(--ink);
  border-color: rgba(26, 18, 11, .14);
}
.card--cream h2,
.card--cream h3,
.card--cream h4 { color: var(--ink); }
.card--cream .note { color: rgba(26, 18, 11, .72); }
.card--cream .label { color: #8A4A1C; }

/* ---------- 10. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 999px;
  border: 1px solid transparent;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: .07em;
  line-height: 1.4;
  transition: transform .22s var(--ease), background .22s var(--ease),
              border-color .22s var(--ease), color .22s var(--ease),
              box-shadow .22s var(--ease);
}
.btn:hover { transform: translateY(-2px); }
.btn--primary {
  background: var(--coral);
  color: var(--ink);
  box-shadow: 0 12px 28px -18px rgba(255, 107, 74, .95);
}
.btn--primary:hover {
  background: #FF8266;
  box-shadow: 0 16px 34px -18px rgba(255, 107, 74, 1);
}
.btn--ghost {
  border-color: rgba(53, 224, 208, .46);
  color: var(--cyan-soft);
  background: rgba(53, 224, 208, .07);
}
.btn--ghost:hover {
  border-color: var(--cyan);
  background: rgba(53, 224, 208, .16);
  color: #FFFFFF;
}
.btn--sand {
  background: var(--sand);
  color: var(--ink);
}
.btn--sand:hover { background: #F7D79B; }

/* ---------- 11. 标签 / 数据块 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 11px;
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  border: 1px solid rgba(53, 224, 208, .36);
  color: var(--cyan);
  background: rgba(53, 224, 208, .09);
}
.tag--coral {
  border-color: rgba(255, 107, 74, .46);
  color: var(--coral);
  background: rgba(255, 107, 74, .11);
}
.tag--sand {
  border-color: rgba(242, 200, 121, .46);
  color: var(--sand);
  background: rgba(242, 200, 121, .11);
}

.stat { display: flex; flex-direction: column; gap: 3px; }
.stat__num {
  font-family: var(--font-mono);
  font-size: clamp(28px, 4vw, 44px);
  font-weight: 700;
  letter-spacing: .02em;
  line-height: 1;
  color: var(--sand);
}
.stat__unit {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  color: rgba(185, 203, 216, .74);
}

/* ---------- 12. 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: rgba(185, 203, 216, .68);
}
.breadcrumb li { display: inline-flex; align-items: center; max-width: none; }
.breadcrumb li + li::before {
  content: "/";
  margin-right: 8px;
  color: rgba(185, 203, 216, .38);
}
.breadcrumb a { color: var(--cyan); }
.breadcrumb a:hover { color: var(--cyan-soft); }

/* ---------- 13. 图片容器基础规则 ---------- */
.media {
  position: relative;
  display: block;
  overflow: hidden;
  border-radius: var(--r-m);
  aspect-ratio: 16 / 10;
  background:
    radial-gradient(120% 90% at 20% 0%, rgba(53, 224, 208, .22), transparent 60%),
    radial-gradient(140% 110% at 100% 100%, rgba(255, 107, 74, .2), transparent 62%),
    linear-gradient(160deg, #123A54, #0C263B);
  border: 1px solid rgba(53, 224, 208, .2);
  box-shadow: inset 0 1px 0 rgba(143, 245, 234, .12);
}
.media > img,
.media > svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(180deg, transparent 52%, rgba(7, 26, 43, .82) 100%);
}
.media--wide { aspect-ratio: 21 / 9; }
.media--tall { aspect-ratio: 4 / 5; }
.media--square { aspect-ratio: 1 / 1; }
.media__caption {
  position: absolute;
  left: 14px;
  right: 14px;
  bottom: 12px;
  z-index: 1;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .1em;
  color: var(--cyan-soft);
}

/* ---------- 14. 动效与显现 ---------- */
html.js [data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity .52s var(--ease), transform .52s var(--ease);
}
html.js [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}
[data-chapter-mark].is-active {
  color: var(--sand);
}
[data-chapter-mark].is-active::before {
  background: var(--coral);
}

@keyframes navDrop {
  from { opacity: 0; transform: translateY(-8px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ---------- 15. 响应式 ---------- */
@media (max-width: 1180px) {
  .tile-strip { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

@media (max-width: 1024px) {
  .footer-top { grid-template-columns: 1fr; }
  .footer-brand__desc { max-width: 46ch; }
}

@media (max-width: 960px) {
  .nav-toggle { display: inline-flex; }
  .tool-link { display: none; }
  .masthead__tag { display: none; }
  .masthead__bar { grid-template-columns: 1fr auto; padding-block: 12px 8px; }
  .brand-lockup { justify-self: start; }

  .site-nav {
    display: none;
    border-top: 1px solid rgba(185, 203, 216, .14);
  }
  .site-header[data-open] .site-nav {
    display: block;
    animation: navDrop .26s var(--ease) both;
  }
  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    padding-block: 10px;
  }
  .nav-link {
    display: block;
    padding: 11px 12px;
    border-radius: var(--r-s);
    font-size: 16px;
  }
  .nav-link::after {
    left: 12px;
    right: auto;
    bottom: 8px;
    width: 26px;
    height: 2px;
  }
  .nav-link:hover { background: rgba(53, 224, 208, .08); }

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

@media (max-width: 900px) {
  body {
    padding-left: 0;
    background-attachment: scroll;
  }
  .brand-rail { display: none; }
  .skip-link { left: 12px; }
}

@media (max-width: 620px) {
  body { font-size: 16px; }
  .tile-strip { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 7px; }
  .tile { padding: 9px 10px; font-size: 12.5px; }
  .brand-lockup__mark { width: 38px; height: 38px; font-size: 14px; }
  .grid--2, .grid--3, .grid--4 { grid-template-columns: 1fr; }
  .footer-nav { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-contact { flex-direction: column; gap: 8px; }
  .footer-base { flex-direction: column; }
  .btn { width: 100%; }
}

/* ---------- 16. 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
  html.js [data-reveal] {
    opacity: 1;
    transform: none;
  }
  .site-header[data-open] .site-nav { animation: none; }
}