/* ===== 底部 Tabbar 3.0 · iOS 液态玻璃（Liquid Glass） =====
   2026-09-19 升级：悬浮式玻璃胶囊 + 滑动镜头指示器 + 弹簧动效
   结构：nav.app-tabbar > a.atab × N + span.atab-lens（由 tabbar-lens.js / mobile-app.js 注入） */
.app-tabbar{display:none}
@media(max-width:768px){
  body{padding-bottom:calc(86px + env(safe-area-inset-bottom,0px))}
  .app-tabbar{
    /* —— 悬浮定位：脱离屏幕边缘，内容可从下方透出 —— */
    display:flex;position:fixed;z-index:1200;
    left:10px;right:10px;bottom:calc(10px + env(safe-area-inset-bottom,0px));
    height:60px;border-radius:30px;
    /* —— 液态玻璃材质：强模糊 + 高饱和 + 微提亮 —— */
    background:linear-gradient(180deg,rgba(255,255,255,.42),rgba(250,250,252,.22));
    -webkit-backdrop-filter:saturate(200%) blur(30px) brightness(1.05);
    backdrop-filter:saturate(200%) blur(30px) brightness(1.05);
    /* —— 光影分层：外阴影悬浮感 + 顶部镜面高光 + 边缘折射描边 —— */
    box-shadow:
      0 12px 32px rgba(0,0,0,.14),
      0 2px 6px rgba(0,0,0,.06),
      inset 0 1px 0 rgba(255,255,255,.85),
      inset 0 -1px 0 rgba(255,255,255,.18),
      inset 0 0 0 .5px rgba(255,255,255,.35);
  }
  /* —— 滑动镜头（液态玻璃的灵魂：选中态不是变色，是一颗滑动的玻璃珠） —— */
  .atab-lens{
    position:absolute;top:5px;bottom:5px;left:0;width:0;
    border-radius:24px;pointer-events:none;z-index:0;
    background:linear-gradient(180deg,rgba(255,255,255,.9),rgba(255,255,255,.45));
    box-shadow:
      inset 0 1px 0 rgba(255,255,255,.95),
      inset 0 0 0 .5px rgba(255,255,255,.5),
      0 2px 10px rgba(0,0,0,.08),
      0 0 0 .5px rgba(0,0,0,.02);
    transition:transform .42s var(--spring,cubic-bezier(.34,1.4,.44,1)),width .42s var(--spring,cubic-bezier(.34,1.4,.44,1));
    will-change:transform;
  }
  .atab-lens::after{ /* 镜头底部的 tint 染色，让选中态可读 */
    content:"";position:absolute;inset:0;border-radius:inherit;
    background:var(--tint,#007AFF);opacity:.10;
  }
  .atab{flex:1;position:relative;z-index:1;display:flex;flex-direction:column;align-items:center;justify-content:center;
    gap:3px;color:var(--sub);-webkit-tap-highlight-color:transparent;text-decoration:none;
    transition:transform .2s var(--ios-spring,cubic-bezier(.32,.72,.24,1)),opacity .18s ease}
  .atab svg{width:23px;height:23px;stroke:currentColor;fill:none;stroke-width:1.7;
    stroke-linecap:round;stroke-linejoin:round;
    transition:transform .3s var(--spring,cubic-bezier(.34,1.4,.44,1))}
  .atab .lb{font-size:10px;font-weight:500;line-height:1;transition:font-weight .2s ease}
  .atab.active{color:var(--tint)}
  .atab.active .lb{font-weight:700}
  .atab.active svg{transform:translateY(-1px) scale(1.06)}
  .atab:active{opacity:.6;transform:scale(.92)}
}
/* —— 深色模式：暗色液态玻璃 —— */
@media(max-width:768px) and (prefers-color-scheme:dark){
  .app-tabbar{
    background:linear-gradient(180deg,rgba(44,44,46,.55),rgba(28,28,30,.38));
    -webkit-backdrop-filter:saturate(180%) blur(30px) brightness(1.02);
    backdrop-filter:saturate(180%) blur(30px) brightness(1.02);
    box-shadow:
      0 12px 32px rgba(0,0,0,.5),
      0 2px 6px rgba(0,0,0,.3),
      inset 0 1px 0 rgba(255,255,255,.22),
      inset 0 -1px 0 rgba(255,255,255,.06),
      inset 0 0 0 .5px rgba(255,255,255,.14);
  }
  .atab-lens{
    background:linear-gradient(180deg,rgba(255,255,255,.22),rgba(255,255,255,.10));
    box-shadow:
      inset 0 1px 0 rgba(255,255,255,.28),
      inset 0 0 0 .5px rgba(255,255,255,.12),
      0 2px 10px rgba(0,0,0,.3);
  }
  .atab-lens::after{opacity:.22}
}
/* —— backdrop-filter 降级 —— */
@supports not ((-webkit-backdrop-filter: blur(1px)) or (backdrop-filter: blur(1px))){
  @media(max-width:768px){
    .app-tabbar{background:var(--bg-card,#fff);box-shadow:0 -1px 12px rgba(0,0,0,.12)}
  }
}