/* 性能三档：只降视觉开销，不砍功能
   high 完整 / mid 均衡 / low 流畅 */
:root[data-perf='mid'] body::before,
:root[data-perf='mid'] body::after,
:root[data-perf='low'] body::before,
:root[data-perf='low'] body::after {
  animation: none !important;
}
:root[data-perf='low'] body::after { filter: none !important; }

/* 低档：全局去掉毛玻璃（这是最贵的一项），改用不透明渐变凑质感 */
:root[data-perf='low'] *,
:root[data-perf='low'] *::before,
:root[data-perf='low'] *::after {
  backdrop-filter: none !important;
  -webkit-backdrop-filter: none !important;
}
:root[data-perf='low'] .topnav,
:root[data-perf='low'] .plan-panel,
:root[data-perf='low'] .panel,
:root[data-perf='low'] .card3d > .face,
:root[data-perf='low'] .study-head,
:root[data-perf='low'] .train-card,
:root[data-perf='low'] .lib-row,
:root[data-perf='low'] .kpi {
  background-image: linear-gradient(180deg, color-mix(in srgb, var(--surface) 97%, transparent), color-mix(in srgb, var(--surface) 90%, transparent)) !important;
}
:root[data-perf='low'] .card3d,
:root[data-perf='low'] .plan-school {
  box-shadow: 0 1px 2px rgba(20, 32, 28, 0.06) !important;
}

/* 低档：关掉入场/阶梯动画与 3D 透视（省掉每帧合成） */
:root[data-perf='low'] .view.is-enter,
:root[data-perf='low'] .lib-row,
:root[data-perf='low'] .plan-school,
:root[data-perf='low'] .train-card,
:root[data-perf='low'] .seg-pill,
:root[data-perf='low'] .card-stage.is-swap-in,
:root[data-perf='low'] .ratings:not(.is-locked) .rating,
:root[data-perf='low'] .splash-tile,
:root[data-perf='low'] .sp-letter,
:root[data-perf='low'] .sp-arc {
  animation: none !important;
  transition-duration: 0.12s !important;
}
:root[data-perf='low'] .card-stage,
:root[data-perf='low'] .card3d {
  perspective: none !important;
  transform-style: flat !important;
}
:root[data-perf='low'] .card3d .face {
  backface-visibility: visible !important;
}

/* 均衡档：保留顶栏和大面板的毛玻璃，关掉列表级与小控件的 */
:root[data-perf='mid'] .chip,
:root[data-perf='mid'] .schip,
:root[data-perf='mid'] .seg-btn,
:root[data-perf='mid'] .mini-select,
:root[data-perf='mid'] .lib-row,
:root[data-perf='mid'] .kpi,
:root[data-perf='mid'] .train-card,
:root[data-perf='mid'] .plan-school,
:root[data-perf='mid'] .qs-row {
  backdrop-filter: none !important;
  -webkit-backdrop-filter: none !important;
}
:root[data-perf='mid'] .lib-row,
:root[data-perf='mid'] .kpi,
:root[data-perf='mid'] .train-card,
:root[data-perf='mid'] .plan-school {
  background-image: linear-gradient(180deg, color-mix(in srgb, var(--surface) 95%, transparent), color-mix(in srgb, var(--surface) 88%, transparent)) !important;
}
:root[data-perf='mid'] .lib-row,
:root[data-perf='mid'] .plan-school {
  content-visibility: auto;
  contain-intrinsic-size: 0 58px;
}

/* 两档都缩短过渡，手感更跟手 */
:root[data-perf='mid'] .btn,
:root[data-perf='mid'] .nav-item,
:root[data-perf='mid'] .lib-row {
  transition-duration: 0.16s !important;
}

@media (prefers-reduced-motion: reduce) {
  :root[data-perf] * { animation-duration: 0.001s !important; }
}