/* ==========================================================================
   盈嘉体育 · 共享站点样式  /assets/site.css
   墨绿赛道长卷 · 荧光青路径 · 橙红行动 · 等宽数据层
   ========================================================================== */

/* ---------- 1. Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 120px;
  background: #061A15;
}
body { margin: 0; min-height: 100%; }
img, picture, svg, video { display: block; max-width: 100%; height: auto; }
button, input, select, textarea { font: inherit; color: inherit; }
button { background: none; border: 0; padding: 0; cursor: pointer; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; margin: 0; padding: 0; }
h1, h2, h3, h4, h5, p, figure, blockquote { margin: 0; }
table { border-collapse: collapse; width: 100%; }

/* ---------- 2. Tokens ---------- */
:root {
  --arena-ink: #061A15;
  --arena-panel: #0C2C24;
  --arena-slate-a: #16212E;
  --arena-slate-b: #22303F;
  --arena-cyan: #2FF3D0;
  --arena-cyan-soft: #A9FFF0;
  --arena-track: #FF5A2B;
  --arena-amber: #FFC46B;
  --arena-text: #E8EEF0;
  --arena-muted: #8A9BA6;
  --arena-line: #1F4A40;
  --arena-quiet: #3A4A48;

  --arena-radius-lg: 28px;
  --arena-radius-md: 22px;
  --arena-radius-sm: 18px;
  --arena-radius-organic: 24px 24px 24px 8px;

  --arena-shell: 1180px;
  --arena-gutter: clamp(16px, 4vw, 52px);
  --arena-step: 8px;

  --arena-font: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --arena-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo,
    Consolas, "Courier New", monospace;

  --arena-ease: cubic-bezier(.2, .75, .2, 1);
}

/* ---------- 3. 基础排版与底色 ---------- */
body {
  font-family: var(--arena-font);
  font-size: 17px;
  line-height: 1.75;
  color: var(--arena-text);
  background-color: var(--arena-ink);
  background-image:
    radial-gradient(88% 58% at 88% -12%, rgba(47, 243, 208, .10), transparent 62%),
    radial-gradient(70% 46% at -6% 6%, rgba(255, 90, 43, .08), transparent 60%),
    repeating-linear-gradient(102deg, rgba(47, 243, 208, .04) 0 1px, transparent 1px 64px);
  background-repeat: no-repeat, no-repeat, repeat;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
::selection { background: var(--arena-cyan); color: var(--arena-ink); }

.arena-mono { font-family: var(--arena-mono); font-variant-numeric: tabular-nums; letter-spacing: .01em; }
.arena-muted { color: var(--arena-muted); }
.arena-quiet { color: var(--arena-quiet); }

.arena-title {
  font-size: clamp(32px, 5vw, 64px);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.03em;
}
.arena-title--md { font-size: clamp(26px, 3.4vw, 40px); letter-spacing: -0.02em; line-height: 1.18; }
.arena-title--sm { font-size: clamp(20px, 2.2vw, 24px); font-weight: 800; letter-spacing: -0.01em; line-height: 1.35; }

.arena-index {
  display: block;
  font-family: var(--arena-mono);
  font-size: 12.5px;
  letter-spacing: .26em;
  color: var(--arena-cyan);
  margin-bottom: 12px;
}
.arena-lede {
  font-size: clamp(16px, 1.6vw, 18.5px);
  line-height: 1.85;
  color: var(--arena-muted);
  max-width: 56ch;
}
.arena-mark {
  text-decoration: underline;
  text-decoration-color: var(--arena-cyan);
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
  font-weight: 500;
}

/* ---------- 4. 布局与通用组件 ---------- */
.arena-shell {
  width: 100%;
  max-width: var(--arena-shell);
  margin-inline: auto;
  padding-inline: var(--arena-gutter);
}
.arena-section { position: relative; padding-block: clamp(48px, 7vw, 112px); }
.arena-section--tight { padding-block: clamp(28px, 4vw, 56px); }
.arena-rule {
  height: 1px;
  border: 0;
  margin-block: clamp(24px, 4vw, 56px);
  background: linear-gradient(90deg, rgba(47, 243, 208, .55), rgba(31, 74, 64, .15) 70%, transparent);
  transform: skewY(-1deg);
}
.arena-stack { display: flex; flex-direction: column; gap: clamp(10px, 1.4vw, 18px); }
.arena-cluster { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; }
.arena-hr { height: 1px; border: 0; background: var(--arena-line); }

.arena-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(14px, 2vw, 26px);
}
.arena-grid--auto { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }
.arena-span-4 { grid-column: span 4; }
.arena-span-5 { grid-column: span 5; }
.arena-span-6 { grid-column: span 6; }
.arena-span-7 { grid-column: span 7; }
.arena-span-8 { grid-column: span 8; }
.arena-span-12 { grid-column: 1 / -1; }

.arena-panel {
  background: linear-gradient(158deg, rgba(12, 44, 36, .92), rgba(22, 33, 46, .74));
  border: 1px solid var(--arena-line);
  border-radius: var(--arena-radius-md);
  padding: clamp(18px, 2.4vw, 28px);
}
.arena-panel--flush { border-radius: var(--arena-radius-organic); }

.arena-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: 999px;
  border: 1px solid var(--arena-line);
  background: rgba(6, 26, 21, .5);
  color: var(--arena-muted);
  font-family: var(--arena-mono);
  font-size: 11.5px;
  letter-spacing: .06em;
  white-space: nowrap;
}
.arena-tag--cyan { border-color: rgba(47, 243, 208, .45); color: var(--arena-cyan); background: rgba(47, 243, 208, .10); }
.arena-tag--amber { border-color: rgba(255, 196, 107, .4); color: var(--arena-amber); background: rgba(255, 196, 107, .10); }
.arena-tag--track { border-color: rgba(255, 90, 43, .45); color: #FF8A63; background: rgba(255, 90, 43, .12); }

/* 按钮 */
.arena-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 22px;
  border-radius: 999px;
  border: 1px solid transparent;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .01em;
  transition: transform .18s var(--arena-ease), background-color .18s ease, border-color .18s ease, color .18s ease;
}
.arena-btn--track { background: var(--arena-track); color: #1A0A04; box-shadow: 0 12px 30px -16px rgba(255, 90, 43, .9); }
.arena-btn--track:hover { background: #FF7A52; transform: translateY(-1px); }
.arena-btn--cyan { background: var(--arena-cyan); color: var(--arena-ink); }
.arena-btn--cyan:hover { background: var(--arena-cyan-soft); transform: translateY(-1px); }
.arena-btn--ghost { border-color: var(--arena-line); background: rgba(12, 44, 36, .6); color: var(--arena-text); }
.arena-btn--ghost:hover { border-color: rgba(47, 243, 208, .5); color: var(--arena-cyan); }
.arena-btn:active { transform: translateY(0); }

/* 面包屑 */
.arena-crumbs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  font-family: var(--arena-mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--arena-muted);
}
.arena-crumbs li { display: inline-flex; align-items: center; gap: 8px; }
.arena-crumbs li::after { content: "/"; color: var(--arena-quiet); }
.arena-crumbs li:last-child::after { content: ""; }
.arena-crumbs a { color: var(--arena-muted); transition: color .18s ease; }
.arena-crumbs a:hover { color: var(--arena-cyan); }
.arena-crumbs [aria-current="page"] { color: var(--arena-cyan-soft); }

/* 正文 */
.arena-prose { max-width: 68ch; font-size: 17px; line-height: 1.8; }
.arena-prose > * + * { margin-top: 1.1em; }
.arena-prose h2 { font-size: clamp(24px, 2.6vw, 32px); font-weight: 800; letter-spacing: -0.02em; line-height: 1.25; margin-top: 2em; }
.arena-prose h3 { font-size: clamp(19px, 2vw, 23px); font-weight: 800; line-height: 1.35; margin-top: 1.6em; }
.arena-prose a { color: var(--arena-cyan); text-decoration: underline; text-underline-offset: 4px; }
.arena-prose strong { color: var(--arena-cyan-soft); font-weight: 700; }
.arena-prose ul { padding-left: 1.1em; list-style: none; }
.arena-prose li { position: relative; padding-left: 1em; margin-top: .5em; }
.arena-prose li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .78em;
  width: 10px;
  height: 2px;
  background: var(--arena-cyan);
}

/* 图片容器（页面阶段放图用） */
.arena-media {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--arena-line);
  border-radius: var(--arena-radius-organic);
  background:
    linear-gradient(158deg, rgba(22, 33, 46, .95), rgba(12, 44, 36, .9)),
    repeating-linear-gradient(102deg, rgba(47, 243, 208, .08) 0 1px, transparent 1px 26px);
}
.arena-media img,
.arena-media video { width: 100%; height: 100%; object-fit: cover; }
.arena-media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(202deg, rgba(255, 90, 43, .16), transparent 44%),
    repeating-linear-gradient(12deg, rgba(47, 243, 208, .09) 0 1px, transparent 1px 18px);
}
.arena-media--tall { aspect-ratio: 3 / 4; }
.arena-media--wide { aspect-ratio: 21 / 9; }
.arena-media--square { aspect-ratio: 1 / 1; }
.arena-media--corner { border-radius: 8px var(--arena-radius-lg) var(--arena-radius-lg) var(--arena-radius-lg); }
.arena-media-data {
  position: absolute;
  left: 14px;
  bottom: 14px;
  z-index: 2;
  padding: 4px 10px;
  border-radius: 999px;
  border: 1px solid rgba(47, 243, 208, .3);
  background: rgba(6, 26, 21, .74);
  color: var(--arena-cyan-soft);
  font-family: var(--arena-mono);
  font-size: 11.5px;
  letter-spacing: .06em;
}

.arena-visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

/* ---------- 5. 头部：悬浮胶囊 ---------- */
.arena-skip {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 120;
  padding: 10px 18px;
  border-radius: 999px;
  background: var(--arena-cyan);
  color: var(--arena-ink);
  font-size: 14px;
  font-weight: 800;
  transform: translateY(-180%);
  transition: transform .2s var(--arena-ease);
}
.arena-skip:focus { transform: translateY(0); }

.arena-header {
  position: sticky;
  top: 0;
  z-index: 60;
  padding: clamp(10px, 1.6vw, 20px) var(--arena-gutter);
  transition: padding .32s var(--arena-ease);
}
.arena-header::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  opacity: 0;
  transition: opacity .3s var(--arena-ease);
  background: linear-gradient(180deg, rgba(6, 26, 21, .96), rgba(6, 26, 21, .62) 58%, rgba(6, 26, 21, 0));
}
.arena-header[data-stuck] { padding-top: 8px; padding-bottom: 8px; }
.arena-header[data-stuck]::before { opacity: 1; }

.arena-header-rail {
  display: flex;
  max-width: var(--arena-shell);
  margin-inline: auto;
}
.arena-header-inner {
  position: relative;
  display: flex;
  align-items: center;
  gap: clamp(10px, 1.6vw, 22px);
  width: 100%;
  max-width: min(100%, 1120px);
  margin-right: auto;
  padding: 10px clamp(12px, 1.8vw, 20px);
  border: 1px solid var(--arena-line);
  border-radius: 999px;
  background: linear-gradient(96deg, rgba(12, 44, 36, .97), rgba(22, 33, 46, .95));
  box-shadow: 0 20px 44px -30px rgba(0, 0, 0, .95);
  transition: max-width .38s var(--arena-ease), padding .32s var(--arena-ease), border-color .3s ease;
}
.arena-header[data-stuck] .arena-header-inner {
  max-width: min(100%, 980px);
  padding-top: 7px;
  padding-bottom: 7px;
  border-color: rgba(47, 243, 208, .3);
}

.arena-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
  min-width: 0;
}
.arena-brand-mark {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  flex: 0 0 auto;
  border: 1px solid rgba(47, 243, 208, .45);
  border-radius: 13px 13px 13px 5px;
  background: linear-gradient(140deg, rgba(47, 243, 208, .24), rgba(47, 243, 208, .04));
  color: var(--arena-cyan);
  font-size: 17px;
  font-weight: 900;
  line-height: 1;
}
.arena-brand-text { display: flex; flex-direction: column; line-height: 1.28; min-width: 0; }
.arena-brand-line { font-size: 15px; font-weight: 800; letter-spacing: -0.01em; white-space: nowrap; }
.arena-brand-desc {
  font-family: var(--arena-mono);
  font-size: 11px;
  letter-spacing: .04em;
  color: var(--arena-muted);
  white-space: nowrap;
}

.arena-nav { display: flex; align-items: center; flex: 1 1 auto; min-width: 0; }
.arena-nav-list { display: flex; align-items: center; gap: 2px; }
.arena-nav-item { display: block; }
.arena-nav-item--cta,
.arena-nav-item--version { display: none; }
.arena-nav-link {
  display: inline-flex;
  align-items: center;
  padding: 8px 12px;
  border-radius: 999px;
  font-size: 14px;
  color: var(--arena-muted);
  white-space: nowrap;
  transition: color .18s ease, background-color .18s ease;
}
.arena-nav-link:hover { color: var(--arena-cyan-soft); background: rgba(47, 243, 208, .09); }
.arena-nav-link[aria-current="page"] {
  color: var(--arena-ink);
  background: var(--arena-cyan);
  font-weight: 700;
}
.arena-nav-link[aria-current="page"]:hover { color: var(--arena-ink); background: var(--arena-cyan-soft); }

.arena-header-tail {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-left: auto;
  flex: 0 0 auto;
}
.arena-version {
  display: inline-flex;
  align-items: center;
  padding: 5px 10px;
  border: 1px solid rgba(255, 196, 107, .3);
  border-radius: 999px;
  background: rgba(255, 196, 107, .12);
  color: var(--arena-amber);
  font-family: var(--arena-mono);
  font-size: 11.5px;
  letter-spacing: .02em;
  white-space: nowrap;
}
.arena-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 9px 18px;
  border-radius: 999px;
  background: var(--arena-track);
  color: #1A0A04;
  font-size: 14px;
  font-weight: 800;
  letter-spacing: .01em;
  white-space: nowrap;
  box-shadow: 0 12px 28px -16px rgba(255, 90, 43, .95);
  transition: transform .18s var(--arena-ease), background-color .18s ease;
}
.arena-cta:hover { background: #FF7A52; transform: translateY(-1px); }
.arena-cta:active { transform: translateY(0); }
.arena-cta--block { display: flex; width: 100%; }

.arena-navtoggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 8px 14px 8px 12px;
  border: 1px solid var(--arena-line);
  border-radius: 999px;
  background: rgba(8, 26, 21, .72);
  color: var(--arena-text);
  font-size: 13px;
  transition: border-color .2s ease, color .2s ease;
}
.arena-navtoggle:hover { border-color: rgba(47, 243, 208, .5); color: var(--arena-cyan); }
.arena-navtoggle-bars { position: relative; display: block; width: 16px; height: 10px; }
.arena-navtoggle-bars::before,
.arena-navtoggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: transform .25s var(--arena-ease), top .25s var(--arena-ease);
}
.arena-navtoggle-bars::before { top: 0; }
.arena-navtoggle-bars::after { top: 8px; }
.arena-navtoggle[aria-expanded="true"] .arena-navtoggle-bars::before { top: 4px; transform: rotate(45deg); }
.arena-navtoggle[aria-expanded="true"] .arena-navtoggle-bars::after { top: 4px; transform: rotate(-45deg); }

.arena-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 2px;
  z-index: 70;
  pointer-events: none;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--arena-cyan), var(--arena-track));
  will-change: transform;
}

/* ---------- 6. 页脚：收束色带 ---------- */
.arena-footer {
  position: relative;
  isolation: isolate;
  margin-top: clamp(72px, 11vw, 150px);
  padding-bottom: clamp(24px, 3vw, 42px);
  border-top: 1px solid var(--arena-line);
  background:
    radial-gradient(80% 62% at 8% 0%, rgba(47, 243, 208, .10), transparent 62%),
    linear-gradient(180deg, var(--arena-slate-a) 0%, #1D2A38 30%, var(--arena-ink) 100%);
  color: var(--arena-text);
}
.arena-footer::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background-image: repeating-linear-gradient(102deg, rgba(47, 243, 208, .05) 0 1px, transparent 1px 64px);
}
.arena-footer-slash {
  width: min(calc(100% - var(--arena-gutter) * 2), var(--arena-shell));
  height: 2px;
  margin: clamp(24px, 4vw, 44px) auto 0;
  transform: skewY(-1.1deg);
  background: linear-gradient(90deg, var(--arena-track), var(--arena-cyan) 38%, rgba(47, 243, 208, 0));
}
.arena-footer-main {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1.5fr);
  gap: clamp(28px, 4vw, 64px);
  padding-block: clamp(32px, 5vw, 62px);
}
.arena-footer-brand { display: flex; flex-direction: column; gap: 14px; max-width: 46ch; }
.arena-footer-logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 17px;
  font-weight: 800;
  letter-spacing: -0.01em;
}
.arena-footer-logo .arena-brand-mark { width: 34px; height: 34px; font-size: 15px; }
.arena-footer-desc { color: var(--arena-muted); font-size: 14.5px; }
.arena-footer-version { font-family: var(--arena-mono); font-size: 12.5px; color: var(--arena-amber); letter-spacing: .02em; }
.arena-footer-contact { display: flex; flex-direction: column; align-items: flex-start; gap: 8px; }
.arena-copy {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 8px 14px;
  border: 1px solid var(--arena-line);
  border-radius: 14px;
  background: rgba(6, 26, 21, .55);
  color: var(--arena-cyan-soft);
  text-align: left;
  transition: border-color .2s ease, background-color .2s ease, color .2s ease;
}
.arena-copy:hover { border-color: rgba(47, 243, 208, .55); background: rgba(47, 243, 208, .10); color: var(--arena-cyan); }
.arena-copy[data-copied="true"] { border-color: var(--arena-cyan); background: rgba(47, 243, 208, .12); color: var(--arena-cyan); }
.arena-copy-value { font-family: var(--arena-mono); font-size: 13px; letter-spacing: -0.01em; word-break: break-all; }
.arena-copy-hint { font-size: 11px; color: var(--arena-muted); white-space: nowrap; }
.arena-copy[data-copied="true"] .arena-copy-hint { color: var(--arena-cyan); }
.arena-footer-address { font-size: 13px; line-height: 1.7; color: var(--arena-muted); }

.arena-footer-nav {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(20px, 3vw, 40px);
}
.arena-footer-title {
  margin-bottom: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--arena-line);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: .16em;
  color: var(--arena-cyan);
}
.arena-footer-list { display: flex; flex-direction: column; gap: 9px; }
.arena-footer-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 14.5px;
  color: var(--arena-muted);
  transition: color .18s ease, transform .2s var(--arena-ease);
}
.arena-footer-link::before {
  content: "";
  width: 10px;
  height: 1px;
  background: currentColor;
  opacity: .55;
  transition: width .2s var(--arena-ease), background-color .2s ease;
}
.arena-footer-link:hover { color: var(--arena-cyan-soft); transform: translateX(2px); }
.arena-footer-link:hover::before { width: 16px; background: var(--arena-cyan); opacity: 1; }

.arena-footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 18px;
  padding-top: clamp(16px, 2.4vw, 26px);
  border-top: 1px solid var(--arena-line);
  font-size: 12.5px;
  color: var(--arena-muted);
}
.arena-footer-closing {
  font-family: var(--arena-mono);
  font-size: 13px;
  letter-spacing: .01em;
  color: var(--arena-cyan-soft);
}
.arena-footer-meta { display: flex; flex-wrap: wrap; align-items: center; gap: 8px 18px; }
.arena-footer-year { font-family: var(--arena-mono); font-variant-numeric: tabular-nums; }

/* ---------- 7. 显现动效 ---------- */
.arena-js [data-reveal] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity .42s var(--arena-ease), transform .42s var(--arena-ease);
  will-change: opacity, transform;
}
.arena-js [data-reveal].is-in { opacity: 1; transform: none; }

/* ---------- 8. 焦点与无障碍 ---------- */
:focus-visible {
  outline: 2px solid var(--arena-cyan);
  outline-offset: 3px;
  border-radius: 6px;
}
.arena-nav-link:focus-visible,
.arena-cta:focus-visible,
.arena-btn:focus-visible { outline-offset: 2px; }
.arena-cta:focus-visible { outline-color: var(--arena-cyan-soft); }

/* ---------- 9. 响应式 ---------- */
@media (max-width: 1150px) {
  .arena-brand-desc { display: none; }
}
@media (max-width: 899px) {
  body { font-size: 16.5px; }
  .arena-header { padding-top: 10px; padding-bottom: 10px; }
  .arena-header-inner { max-width: 100%; border-radius: 30px; }
  .arena-header[data-stuck] .arena-header-inner { max-width: 100%; }
  .arena-header-tail .arena-version,
  .arena-header-tail .arena-cta { display: none; }
  .arena-navtoggle { display: inline-flex; }
  .arena-nav {
    position: absolute;
    top: calc(100% + 10px);
    left: 0;
    right: 0;
    display: block;
    padding: 10px;
    border: 1px solid var(--arena-line);
    border-radius: var(--arena-radius-md);
    background: #0B2620;
    box-shadow: 0 30px 62px -30px rgba(0, 0, 0, .95);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity .22s ease, transform .3s var(--arena-ease), visibility .22s;
  }
  .arena-nav[data-open] { opacity: 1; visibility: visible; transform: none; }
  .arena-nav-list { flex-direction: column; align-items: stretch; gap: 4px; }
  .arena-nav-link { padding: 13px 14px; border-radius: 16px; font-size: 16px; }
  .arena-nav-item--cta,
  .arena-nav-item--version { display: block; }
  .arena-nav-item--cta { margin-top: 6px; }
  .arena-nav-item--version {
    margin-top: 6px;
    padding: 10px 4px 2px;
    border-top: 1px solid var(--arena-line);
  }
  .arena-footer-main { grid-template-columns: minmax(0, 1fr); }
}
@media (max-width: 900px) {
  .arena-grid { grid-template-columns: repeat(6, minmax(0, 1fr)); }
  .arena-span-4,
  .arena-span-5,
  .arena-span-7,
  .arena-span-8 { grid-column: span 6; }
}
@media (max-width: 620px) {
  .arena-brand-line { font-size: 14px; }
  .arena-footer-nav { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .arena-footer-base { flex-direction: column; align-items: flex-start; }
  .arena-copy { width: 100%; justify-content: space-between; }
}

/* ---------- 10. 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    transition-delay: 0ms !important;
  }
  .arena-js [data-reveal],
  [data-reveal] { opacity: 1 !important; transform: none !important; transition: none !important; }
  .arena-cta:hover,
  .arena-btn:hover,
  .arena-footer-link:hover { transform: none; }
}