/* A · 清爽学习台 — shared design tokens, light first, explicit dark compatibility. */
:root{
  --ui-bg:#f1f5fb;
  --ui-surface:#ffffff;
  --ui-inset:#f5f8fc;
  --ui-soft:#eaf3ff;
  --ui-ink:#09213f;
  --ui-muted:#4f647d;
  --ui-faint:#5a6f87;
  --ui-line:#dce5ef;
  --ui-border:#b2c4d9;
  --ui-blue:#0877ff;
  --ui-action:#075fce;
  --ui-sky:#42b7ff;
  --ui-yellow:#ffd31a;
  --ui-amber:#ffb020;
  --ui-warm-ink:#765600;
  --ui-success:#08783b;
  --ui-error:#b9223a;
  --ui-font-ui:"Segoe UI","Microsoft YaHei","PingFang SC",sans-serif;
  --ui-font-reading:Georgia,"Times New Roman","Microsoft YaHei",serif;
  --ui-text-xs:12px;
  --ui-text-sm:13px;
  --ui-text-md:14px;
  --ui-text-body:15px;
  --ui-text-lg:18px;
  --ui-text-xl:24px;
  --ui-text-title:30px;
  --ui-radius-xs:6px;
  --ui-radius-sm:10px;
  --ui-radius-md:12px;
  --ui-radius-card:18px;
  --ui-radius-dialog:22px;
  --ui-radius-pill:999px;
  --ui-space-1:4px;
  --ui-space-2:8px;
  --ui-space-3:12px;
  --ui-space-4:16px;
  --ui-space-5:20px;
  --ui-space-6:24px;
  --ui-space-7:32px;
  --ui-space-8:48px;
  --ui-sidebar:216px;
  --ui-content:1000px;
  --ui-reading:900px;
  --ui-tap:44px;
  --ui-shadow:0 8px 26px #09213f04;
}
:root[data-theme="dark"]{
  --ui-bg:#0b1625;--ui-surface:#132237;--ui-inset:#0e1b2d;--ui-soft:#1a3350;
  --ui-ink:#ebf2fc;--ui-muted:#bdcce0;--ui-faint:#a5b9d0;
  --ui-line:#30445e;--ui-border:#58718d;--ui-action:#92d3ff;
  --ui-warm-ink:#ffdc66;--ui-success:#6fe0a4;--ui-error:#ff9eac;
  --ui-shadow:none;
}