/* foundation.css — 基础重置与全局变量 */
*,*::before,*::after{box-sizing:border-box}

:root{
  --brand:#2563eb;
  --brand-dark:#1d4ed8;
  --brand-soft:#eff4ff;
  --accent:#06b6d4;
  --ink:#0f172a;
  --text:#1f2937;
  --muted:#5b6474;
  --line:#e5e7eb;
  --bg:#ffffff;
  --bg-soft:#f6f9ff;
  --bg-dark:#0b1424;
  --radius-sm:10px;
  --radius:14px;
  --radius-lg:20px;
  --maxw:1200px;
  --gap:clamp(24px,4vw,64px);
  --shadow:0 12px 32px rgba(23,42,89,.08);
  --font:system-ui,-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
}

html{-webkit-text-size-adjust:100%}
body{
  margin:0;
  font-family:var(--font);
  font-size:1rem;
  line-height:1.7;
  color:var(--text);
  background:var(--bg);
  -webkit-font-smoothing:antialiased;
}

img,svg{max-width:100%;height:auto;display:block}
a{color:var(--brand);text-decoration:none}
a:hover{color:var(--brand-dark)}

h1,h2,h3,h4{color:var(--ink);margin:0 0 .6em;line-height:1.28;font-weight:700}
h1{font-size:clamp(2rem,4vw,3rem)}
h2{font-size:clamp(1.5rem,2.4vw,2rem)}
h3{font-size:1.125rem;font-weight:600}
p{margin:0 0 1em}
p:last-child{margin-bottom:0}

ul,ol{margin:0 0 1em;padding-left:1.2em}
li{margin:.35em 0}

button{font:inherit;cursor:pointer}

:focus-visible{outline:2px solid var(--brand);outline-offset:3px;border-radius:4px}