/* Qihang design tokens — brand orange from the site header CTA. */
:root{
  --brand:#FF4D00;
  --brand-2:#FF6A2B;
  --brand-dark:#E03D00;
  --brand-soft:#FFF3ED;
  --brand-shadow:rgba(255,77,0,.22);

  --bg:#F0F7FF;
  --bg-2:#F8FAFC;
  --surface:#FFFFFF;
  --surface-soft:#F7FBFF;

  --ink:#1F2937;
  --sub:#5B6B7F;
  --muted:#94A3B8;
  --line:rgba(31,41,55,.09);
  --line-strong:rgba(31,41,55,.14);

  --green:#0C8A4A;
  --green-soft:#EAF8F0;
  --red:#C0392B;
  --red-soft:#FFF1F0;

  --radius-sm:8px;
  --radius-md:12px;
  --radius-lg:16px;
  --radius-xl:20px;
  --shadow-sm:0 8px 24px rgba(31,41,55,.06);
  --shadow-md:0 20px 50px rgba(31,41,55,.09);
  --font:"PingFang SC","Microsoft YaHei","Noto Sans SC","Source Han Sans SC","Hiragino Sans GB",system-ui,-apple-system,"Segoe UI",sans-serif;
}
*{box-sizing:border-box}
html,body{margin:0;min-height:100%}
body{
  background:var(--bg);
  color:var(--ink);
  font-family:var(--font);
  font-size:16px;
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit}
svg{display:block}
.icon{fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
::selection{background:rgba(255,77,0,.18);color:var(--ink)}