/* =========================================================
   博赢BY · 共享样式 /assets/site.css
   深墨蓝基底 + 电光青（新版）/ 琥珀橙（上一版）双语义强调
   ========================================================= */

/* ---------- 1. reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; text-size-adjust: 100%; scroll-behavior: smooth; }
body, h1, h2, h3, h4, h5, h6, p, ul, ol, li, figure, blockquote, dl, dt, dd { margin: 0; padding: 0; }
ul, ol { list-style: none; }
img, svg, video { display: block; max-width: 100%; height: auto; }
button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
a { color: inherit; text-decoration: none; }
hr { border: 0; }

/* ---------- 2. tokens ---------- */
:root {
  --ink: #0A1A2F;
  --ink-2: #0E2438;
  --ink-3: #173349;
  --cyan: #2FD8D0;
  --cyan-soft: #8CEFE8;
  --amber: #FF9B3D;
  --amber-soft: #FFC98A;
  --mist: #EDF1F5;
  --graphite: #0D1620;
  --wire: #C7D2DC;
  --muted: #9AA9B8;

  --font-head: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-body: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;

  --gutter: 24px;
  --container: 1200px;
  --frame-max: 1440px;
  --cut: 22px;
  --cut-sm: 14px;

  --hair: rgba(199, 210, 220, .18);
  --hair-strong: rgba(199, 210, 220, .34);
  --ease: cubic-bezier(.2, .75, .3, 1);
}

/* ---------- 3. base ---------- */
body {
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.75;
  font-weight: 400;
  letter-spacing: .01em;
  color: var(--mist);
  background-color: var(--ink);
  background-image:
    radial-gradient(1100px 620px at 82% -10%, rgba(47, 216, 208, .08), transparent 62%),
    radial-gradient(880px 520px at 4% 14%, rgba(255, 155, 61, .055), transparent 64%);
  background-repeat: no-repeat;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 { font-family: var(--font-head); font-weight: 900; letter-spacing: -.02em; line-height: 1.18; color: #fff; }
p { text-wrap: pretty; }

:focus-visible { outline: 2px solid var(--amber); outline-offset: 3px; }

/* ---------- 4. 排版原子 ---------- */
.display { font-family: var(--font-head); font-weight: 900; font-size: clamp(40px, 6vw, 72px); line-height: 1.04; letter-spacing: -.03em; color: #fff; }
.page-title { font-family: var(--font-head); font-weight: 900; font-size: clamp(30px, 3.6vw, 44px); line-height: 1.14; letter-spacing: -.025em; color: #fff; }
.section-title { font-family: var(--font-head); font-weight: 900; font-size: clamp(20px, 2vw, 26px); line-height: 1.24; letter-spacing: -.02em; color: #fff; }
.card-title { font-family: var(--font-head); font-size: 18px; font-weight: 800; letter-spacing: -.01em; color: #fff; }
.lead { font-size: 17px; line-height: 1.75; color: var(--mist); max-width: 36ch; }
.prose { max-width: 36ch; }
.prose--wide { max-width: 62ch; }
.prose p + p { margin-top: 16px; }
.muted { color: var(--muted); }
.mono { font-family: var(--font-mono); font-weight: 500; font-variant-numeric: tabular-nums; letter-spacing: .02em; }
.annot { font-size: 12px; letter-spacing: .16em; line-height: 1.5; color: var(--muted); }
.annot--vertical { writing-mode: vertical-rl; text-orientation: mixed; letter-spacing: .16em; }
.eyebrow { display: inline-block; font-size: 12px; letter-spacing: .16em; font-weight: 700; color: var(--cyan-soft); }

/* ---------- 5. 布局工具 ---------- */
.wrap { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 24px; }
.wrap--wide { max-width: var(--frame-max); }
.section { padding: clamp(48px, 6vw, 88px) 0; }
.section-head { display: flex; align-items: baseline; justify-content: space-between; gap: 20px 28px; flex-wrap: wrap; margin-bottom: 28px; }
.hairline { height: 1px; background: var(--hair); }
.page-head { position: relative; padding: 36px 0 26px; }
.page-head .display, .page-head .page-title { max-width: 26ch; }

/* ---------- 6. skip link ---------- */
.skip-link {
  position: fixed; left: 16px; top: 16px; z-index: 200;
  padding: 11px 18px;
  font-size: 14px; font-weight: 700; letter-spacing: .04em;
  color: var(--graphite); background: var(--amber);
  clip-path: polygon(8px 0, 100% 0, 100% calc(100% - 8px), calc(100% - 8px) 100%, 0 100%, 0 8px);
  transform: translateY(-220%);
  transition: transform .18s var(--ease);
}
.skip-link:focus-visible { transform: translateY(0); outline-offset: 2px; }

/* ---------- 7. header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 90;
  background: rgba(10, 26, 47, .94);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--hair);
  transition: box-shadow .22s var(--ease);
}
.site-header[data-collapsed] { box-shadow: 0 12px 32px rgba(0, 0, 0, .34); }

.scroll-progress {
  position: absolute; left: 0; top: 0; height: 2px; width: 100%;
  transform: scaleX(0); transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--cyan), var(--amber));
  pointer-events: none;
}

.header-frame {
  position: relative;
  max-width: var(--frame-max);
  margin: 0 auto;
  padding: 16px 28px 16px 34px;
  min-height: 78px;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 26px;
  transition: min-height .22s var(--ease), padding .22s var(--ease);
}
.site-header[data-collapsed] .header-frame { min-height: 60px; padding-top: 8px; padding-bottom: 8px; }

.header-frame::after {
  content: ""; position: absolute; right: 0; bottom: 9px; width: 68px; height: 1px;
  background: linear-gradient(90deg, rgba(47, 216, 208, 0), var(--cyan));
  transform: rotate(-12deg); transform-origin: right center;
  pointer-events: none;
}

.frame-notch {
  position: absolute; left: 0; top: 0; bottom: 0; width: 10px;
  background: linear-gradient(180deg, var(--cyan), rgba(47, 216, 208, .06));
  overflow: hidden;
}
.frame-notch::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: 0; height: 28px;
  background: var(--amber);
  transform: skewY(12deg); transform-origin: bottom left;
}

.brand { position: relative; display: flex; flex-direction: column; gap: 1px; padding-left: 15px; min-width: 0; }
.brand::before {
  content: ""; position: absolute; left: 0; top: 3px; bottom: 3px; width: 3px;
  background: var(--cyan-soft); transform: skewY(-12deg);
}
.brand-mark { font-family: var(--font-head); font-size: 23px; font-weight: 900; letter-spacing: -.02em; line-height: 1.1; color: #fff; white-space: nowrap; }
.brand-subline { font-size: 12px; letter-spacing: .16em; color: var(--muted); white-space: nowrap; transition: opacity .2s var(--ease); }
.site-header[data-collapsed] .brand-subline { opacity: 0; }

.primary-nav { justify-self: center; min-width: 0; }
.nav-list { display: flex; align-items: center; gap: 2px; }
.nav-item { display: block; }
.nav-link {
  display: block; position: relative;
  padding: 10px 14px;
  font-size: 15px; font-weight: 500; letter-spacing: .02em;
  color: var(--mist);
  transition: color .18s var(--ease), background-color .18s var(--ease);
}
.nav-link::after {
  content: ""; position: absolute; left: 14px; right: 14px; bottom: 6px; height: 2px;
  background: var(--cyan);
  transform: scaleX(0); transform-origin: left center;
  transition: transform .2s var(--ease);
}
.nav-link:hover { color: #fff; }
.nav-link:hover::after { transform: scaleX(1); }
.nav-link[aria-current="page"] { color: #fff; background: rgba(47, 216, 208, .1); }
.nav-link[aria-current="page"]::after { background: var(--amber); transform: scaleX(1); }

.header-utility { display: flex; align-items: center; gap: 18px; justify-self: end; }

.update-lamp { display: inline-flex; align-items: center; gap: 8px; font-size: 12.5px; letter-spacing: .1em; color: var(--muted); white-space: nowrap; }
.lamp {
  display: block; width: 8px; height: 8px; flex: 0 0 8px;
  background: var(--amber);
  box-shadow: 0 0 0 4px rgba(255, 155, 61, .16);
  animation: lamp-pulse 2.6s var(--ease) infinite;
}
@keyframes lamp-pulse {
  0%, 100% { opacity: 1; box-shadow: 0 0 0 4px rgba(255, 155, 61, .16); }
  50% { opacity: .55; box-shadow: 0 0 0 7px rgba(255, 155, 61, .05); }
}

.utility-item {
  font-size: 13px; letter-spacing: .06em; color: var(--muted);
  padding: 6px 0; border-bottom: 1px solid transparent;
  transition: color .18s var(--ease), border-color .18s var(--ease);
}
.utility-item:hover { color: var(--cyan-soft); border-bottom-color: var(--cyan); }

.header-cta {
  display: inline-flex; align-items: center;
  padding: 11px 20px;
  font-size: 14px; font-weight: 800; letter-spacing: .02em;
  color: var(--graphite); background: var(--cyan);
  white-space: nowrap;
  clip-path: polygon(10px 0, 100% 0, 100% calc(100% - 10px), calc(100% - 10px) 100%, 0 100%, 0 10px);
  transition: transform .18s var(--ease), background-color .18s var(--ease);
}
.header-cta:hover { background: var(--cyan-soft); transform: translateY(-2px); }

.nav-toggle {
  display: none; align-items: center; gap: 9px;
  padding: 9px 12px;
  border: 1px solid var(--hair-strong);
  color: var(--mist); font-size: 13px; letter-spacing: .1em;
  transition: border-color .18s var(--ease), color .18s var(--ease);
}
.nav-toggle:hover { border-color: var(--cyan); color: #fff; }
.nav-toggle-text { font-size: 13px; }
.nav-toggle-bars { position: relative; display: block; width: 18px; height: 2px; background: var(--cyan); }
.nav-toggle-bars::before, .nav-toggle-bars::after {
  content: ""; position: absolute; left: 0; width: 18px; height: 2px; background: var(--cyan);
  transition: transform .2s var(--ease), opacity .2s var(--ease);
}
.nav-toggle-bars::before { top: -6px; }
.nav-toggle-bars::after { top: 6px; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars { background: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::before { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::after { transform: translateY(-6px) rotate(-45deg); }

/* ---------- 8. footer ---------- */
.site-footer {
  position: relative;
  margin-top: 120px;
  background-color: var(--ink-2);
  background-image:
    linear-gradient(rgba(199, 210, 220, .045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(199, 210, 220, .045) 1px, transparent 1px);
  background-size: 40px 40px;
  border-top: 1px solid var(--hair);
}
.site-footer::before {
  content: ""; position: absolute; left: 0; right: 0; top: 0; height: 2px;
  background: linear-gradient(90deg, var(--cyan), rgba(47, 216, 208, 0) 48%, var(--amber));
}

.footer-frame {
  position: relative;
  max-width: var(--frame-max);
  margin: 0 auto;
  padding: 72px 28px 48px;
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 2.1fr) minmax(0, 1.2fr);
  gap: 48px;
}

.footer-lead { position: relative; display: flex; flex-direction: column; gap: 8px; padding-left: 16px; }
.footer-lead::before {
  content: ""; position: absolute; left: 0; top: 6px; bottom: 6px; width: 3px;
  background: var(--cyan); transform: skewY(-12deg);
}
.footer-brand { font-family: var(--font-head); font-size: 26px; font-weight: 900; letter-spacing: -.02em; line-height: 1.2; color: #fff; }
.footer-subline { font-size: 12px; letter-spacing: .16em; color: var(--muted); }
.footer-update { display: flex; align-items: flex-start; gap: 9px; margin-top: 10px; font-size: 13px; line-height: 1.7; color: var(--mist); max-width: 26ch; }
.footer-update .lamp { margin-top: 8px; }

.footer-columns { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 32px; }
.footer-col { display: flex; flex-direction: column; gap: 14px; }
.footer-col-title {
  font-size: 12px; font-weight: 700; letter-spacing: .16em; color: var(--cyan-soft);
  padding-bottom: 10px; border-bottom: 1px solid var(--hair);
}
.footer-links { display: flex; flex-direction: column; gap: 9px; }
.footer-links a {
  position: relative; display: inline-block; padding-left: 14px;
  font-size: 15px; color: var(--mist);
  transition: color .18s var(--ease), padding-left .18s var(--ease);
}
.footer-links a::before {
  content: ""; position: absolute; left: 0; top: .78em; width: 6px; height: 1px; background: var(--muted);
  transition: background-color .18s var(--ease), width .18s var(--ease);
}
.footer-links a:hover { color: #fff; padding-left: 19px; }
.footer-links a:hover::before { background: var(--amber); width: 11px; }

.footer-contact { display: flex; flex-direction: column; gap: 14px; }
.contact-list { display: flex; flex-direction: column; gap: 11px; }
.contact-line { display: flex; flex-direction: column; gap: 2px; font-size: 14px; line-height: 1.6; color: var(--mist); word-break: break-word; }
.contact-key { font-size: 12px; letter-spacing: .14em; color: var(--muted); }
.contact-note { font-size: 13px; line-height: 1.7; color: var(--muted); max-width: 30ch; }

.footer-legal {
  max-width: var(--frame-max);
  margin: 0 auto;
  padding: 20px 28px 34px;
  border-top: 1px solid var(--hair);
  display: flex; flex-wrap: wrap; align-items: center; gap: 8px 24px;
  font-size: 12.5px; letter-spacing: .04em; color: var(--muted);
}
.legal-icp { color: var(--muted); }
.legal-note { color: var(--muted); }
.legal-year { margin-left: auto; }

.to-top {
  position: fixed; right: 22px; bottom: 26px; z-index: 80;
  padding: 11px 16px;
  font-size: 13px; font-weight: 700; letter-spacing: .06em;
  color: var(--graphite); background: var(--amber);
  clip-path: polygon(9px 0, 100% 0, 100% calc(100% - 9px), calc(100% - 9px) 100%, 0 100%, 0 9px);
  opacity: 0; visibility: hidden; transform: translateY(8px);
  transition: opacity .2s var(--ease), transform .2s var(--ease), visibility .2s linear;
}
.to-top[data-visible] { opacity: 1; visibility: visible; transform: translateY(0); }

/* ---------- 9. 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 9px;
  padding: 13px 22px;
  font-size: 15px; font-weight: 700; letter-spacing: .02em;
  color: var(--graphite); background: var(--cyan);
  clip-path: polygon(10px 0, 100% 0, 100% calc(100% - 10px), calc(100% - 10px) 100%, 0 100%, 0 10px);
  transition: transform .18s var(--ease), background-color .18s var(--ease), color .18s var(--ease);
}
.btn:hover { transform: translateY(-2px); background: var(--cyan-soft); }
.btn--amber { background: var(--amber); }
.btn--amber:hover { background: var(--amber-soft); }
.btn--line { background: rgba(199, 210, 220, .08); color: var(--mist); }
.btn--line:hover { background: rgba(47, 216, 208, .12); color: #fff; }

/* ---------- 10. 标签 ---------- */
.tag {
  display: inline-flex; align-items: center;
  padding: 5px 11px;
  font-size: 12px; font-weight: 700; letter-spacing: .1em;
  color: var(--cyan-soft); background: rgba(47, 216, 208, .1);
  clip-path: polygon(7px 0, 100% 0, 100% calc(100% - 7px), calc(100% - 7px) 100%, 0 100%, 0 7px);
}
.tag--amber { color: var(--amber-soft); background: rgba(255, 155, 61, .12); }
.tag--plain { color: var(--muted); background: rgba(199, 210, 220, .08); }

/* ---------- 11. Bento 网格 ---------- */
.bento { display: grid; grid-template-columns: repeat(12, minmax(0, 1fr)); gap: var(--gutter); align-items: start; }
.bento > * { grid-column: span 12; min-width: 0; }

@media (min-width: 768px) and (max-width: 1099px) {
  .bento > [data-span="3"], .bento > [data-span="4"] { grid-column: span 6; }
  .bento > [data-span="5"], .bento > [data-span="6"], .bento > [data-span="7"],
  .bento > [data-span="8"], .bento > [data-span="9"], .bento > [data-span="12"] { grid-column: span 12; }
}
@media (min-width: 1100px) {
  .bento > [data-span="3"] { grid-column: span 3; }
  .bento > [data-span="4"] { grid-column: span 4; }
  .bento > [data-span="5"] { grid-column: span 5; }
  .bento > [data-span="6"] { grid-column: span 6; }
  .bento > [data-span="7"] { grid-column: span 7; }
  .bento > [data-span="8"] { grid-column: span 8; }
  .bento > [data-span="9"] { grid-column: span 9; }
  .bento > [data-span="12"] { grid-column: span 12; }
}

/* ---------- 12. 切角面板 ---------- */
.panel {
  position: relative;
  background: var(--ink-2);
  padding: 26px 26px 28px;
  clip-path: polygon(var(--cut) 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%, 0 var(--cut));
  transition: transform .2s var(--ease), background-color .2s var(--ease);
}
.panel--tight { --cut: var(--cut-sm); padding: 18px 18px 20px; }
.panel--nest { background: var(--ink-3); }
.panel--focus { background: linear-gradient(160deg, rgba(47, 216, 208, .16), rgba(14, 36, 56, .98) 58%); }
.panel--mark { background: linear-gradient(160deg, rgba(255, 155, 61, .15), rgba(14, 36, 56, .98) 60%); }
.panel--light { background: var(--mist); color: var(--graphite); }
.panel--light .panel-title, .panel--light .card-title { color: var(--graphite); }
.panel--light .panel-body, .panel--light p { color: var(--graphite); }
.panel:hover { transform: translateY(-2px); }

.panel-top { display: flex; align-items: center; justify-content: space-between; gap: 16px; margin-bottom: 14px; flex-wrap: wrap; }
.panel-title { font-family: var(--font-head); font-size: 18px; font-weight: 800; letter-spacing: -.01em; color: #fff; }
.panel-body { font-size: 16px; line-height: 1.75; color: var(--mist); }
.panel-note { margin-top: 14px; font-size: 12px; letter-spacing: .14em; color: var(--muted); }
.panel-edge { position: absolute; left: 0; right: 0; top: 0; height: 3px; background: var(--cyan); }
.panel-edge--amber { background: var(--amber); }

/* ---------- 13. 新旧对照 ---------- */
.compare { display: grid; grid-template-columns: 5fr 7fr; gap: var(--gutter); align-items: start; }
.compare-col {
  position: relative;
  background: var(--ink-2);
  padding: 24px 24px 26px;
  border-top: 3px solid var(--cyan);
  clip-path: polygon(var(--cut) 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%, 0 var(--cut));
}
.compare-col--prev { border-top-color: var(--amber); }
.compare-col--prev .compare-value { color: var(--amber-soft); }
.compare-value { font-family: var(--font-mono); font-weight: 500; color: var(--cyan-soft); }

/* ---------- 14. 面包屑 / 目录 ---------- */
.breadcrumb { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; padding: 18px 0 0; font-size: 12.5px; letter-spacing: .06em; color: var(--muted); }
.breadcrumb li { display: flex; align-items: center; gap: 8px; }
.breadcrumb li + li::before { content: ""; display: block; width: 8px; height: 1px; background: var(--hair-strong); }
.breadcrumb a { transition: color .18s var(--ease); }
.breadcrumb a:hover { color: var(--cyan-soft); }
.breadcrumb [aria-current="page"] { color: var(--mist); }

.dir-link {
  display: block;
  padding: 6px 0 6px 12px;
  border-left: 1px solid var(--hair);
  font-size: 13px; letter-spacing: .06em; color: var(--muted);
  transition: color .18s var(--ease), border-color .18s var(--ease);
}
.dir-link:hover { color: var(--mist); }
.dir-link[aria-current="true"] { color: var(--cyan-soft); border-left-color: var(--cyan); }

/* ---------- 15. 图片容器 ---------- */
.media-frame {
  position: relative;
  aspect-ratio: 16 / 10;
  overflow: hidden;
  background: var(--ink-3);
  clip-path: polygon(var(--cut) 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%, 0 var(--cut));
}
.media-frame > img, .media-frame > picture > img { width: 100%; height: 100%; object-fit: cover; }
.media-frame::after {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background-image:
    linear-gradient(rgba(199, 210, 220, .07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(199, 210, 220, .07) 1px, transparent 1px);
  background-size: 32px 32px;
}
.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--tall { aspect-ratio: 4 / 5; }
.media-frame--square { aspect-ratio: 1 / 1; }
.media-frame figcaption {
  position: absolute; left: 16px; bottom: 14px; z-index: 2;
  padding: 5px 10px;
  font-size: 12px; letter-spacing: .14em; color: var(--mist);
  background: rgba(10, 26, 47, .74);
}

/* ---------- 16. 显现动效 ---------- */
.js [data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity .24s var(--ease), transform .24s var(--ease);
}
.js [data-reveal].is-revealed { opacity: 1; transform: none; }

/* ---------- 17. 响应式 ---------- */
@media (max-width: 1180px) {
  .header-frame { gap: 18px; }
  .utility-item { display: none; }
}

@media (max-width: 960px) {
  .header-frame {
    grid-template-columns: minmax(0, 1fr) auto;
    min-height: 64px;
    padding: 10px 16px 10px 24px;
    gap: 14px;
  }
  .site-header[data-collapsed] .header-frame { min-height: 56px; }
  .header-frame::after { display: none; }
  .brand-subline { display: none; }
  .update-lamp { display: none; }
  .nav-toggle { display: inline-flex; }

  .primary-nav {
    position: absolute; left: 0; right: 0; top: 100%;
    justify-self: stretch;
    background: var(--ink-2);
    border-top: 1px solid var(--hair);
    border-bottom: 1px solid var(--hair);
    max-height: 0;
    overflow: hidden;
    visibility: hidden;
    transition: max-height .28s var(--ease), visibility .28s linear;
  }
  .primary-nav[data-open] { max-height: 78vh; overflow-y: auto; visibility: visible; }
  .nav-list { flex-direction: column; align-items: stretch; gap: 0; padding: 10px 16px 22px; }
  .nav-link { padding: 15px 10px; font-size: 16px; border-bottom: 1px solid var(--hair); }
  .nav-link::after { left: 10px; right: auto; width: 46px; }
  .nav-link[aria-current="page"] { background: rgba(47, 216, 208, .08); }

  .site-footer { margin-top: 88px; }
  .compare { grid-template-columns: 1fr; }
}

@media (max-width: 1100px) {
  .footer-frame { grid-template-columns: minmax(0, 1fr) minmax(0, 1.6fr); gap: 40px; }
  .footer-contact { grid-column: 1 / -1; }
}

@media (max-width: 720px) {
  body { font-size: 16px; }
  .wrap { padding: 0 18px; }
  .header-cta { padding: 10px 13px; font-size: 13px; letter-spacing: 0; }
  .footer-frame { grid-template-columns: 1fr; padding: 52px 18px 32px; gap: 34px; }
  .footer-columns { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 26px; }
  .footer-legal { padding: 18px 18px 30px; }
  .legal-year { margin-left: 0; }
  .to-top { right: 14px; bottom: 16px; }
}

@media (max-width: 420px) {
  .brand-mark { font-size: 20px; }
  .header-cta { display: none; }
  .footer-columns { grid-template-columns: 1fr; }
}

/* ---------- 18. 动效与可访问性偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
  .js [data-reveal] { opacity: 1; transform: none; }
  .panel:hover, .btn:hover, .header-cta:hover { transform: none; }
  .to-top { transform: none; }
}