:root{
  --bg:#f4f6f8; --panel:#ffffff; --ink:#1f2a33; --muted:#5b6b75;
  --line:#dfe6ea; --brand:#1e6f5c; --brand2:#2a9d8f; --accent:#0b7285;
  --warn:#b9541b; --ok:#2f9e44; --chip:#e8eef0;
}
*{box-sizing:border-box}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue","Noto Sans",Arial,"PingFang SC","Microsoft YaHei",sans-serif;
  color:var(--ink);background:var(--bg);line-height:1.5;font-size:15px}
.topbar{display:flex;justify-content:space-between;align-items:center;gap:12px;
  padding:10px 18px;background:var(--brand);color:#fff;position:sticky;top:0;z-index:50;flex-wrap:wrap}
.topbar a{color:#fff;text-decoration:none;font-weight:600}
.topbar a:hover{text-decoration:underline}
.tb-sep{opacity:.5;margin:0 8px}
.tb-lang{font-size:13px;display:flex;align-items:center;gap:6px}
.tb-lang select{padding:3px 6px;border-radius:6px;border:1px solid rgba(255,255,255,.4);background:#fff;color:var(--ink)}
.container{max-width:1080px;margin:0 auto;padding:22px 18px 40px}
.module{max-width:860px}
h1{font-size:24px;margin:.2em 0 .1em}
h2{font-size:18px;margin:1.4em 0 .5em;color:var(--brand)}
.tagline{color:var(--muted);margin-top:0}
.back-link{display:inline-block;margin:4px 0 8px;color:var(--accent);text-decoration:none;font-weight:600}
.back-link:hover{text-decoration:underline}
.cat-block{margin-bottom:8px}
.card-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:12px}
.card{display:block;background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:16px;
  text-decoration:none;color:var(--ink);transition:.15s;box-shadow:0 1px 2px rgba(0,0,0,.03)}
.card:hover{border-color:var(--brand2);transform:translateY(-2px);box-shadow:0 4px 12px rgba(30,111,92,.12)}
.card-title{font-weight:700;font-size:15px}
.panel{background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:16px 18px;margin:14px 0}
.section-h{font-weight:700;margin:.4em 0 .6em;color:var(--brand2)}
.field{margin:10px 0}
.field label{display:block;font-weight:600;margin-bottom:4px}
.field-row{display:flex;align-items:center;gap:8px}
.field input,.field select{width:100%;max-width:280px;padding:8px 10px;border:1px solid var(--line);border-radius:8px;font-size:15px}
.field .unit{color:var(--muted);font-size:14px}
.hint{display:block;color:var(--muted);font-size:12.5px;margin-top:3px}
.results{margin-top:8px}
.result{display:flex;align-items:baseline;gap:8px;padding:8px 0;border-bottom:1px dashed var(--line)}
.result:last-child{border-bottom:none}
.r-label{flex:1;font-weight:600}
.r-value{font-variant-numeric:tabular-nums;font-weight:700;color:var(--brand);font-size:17px}
.r-unit{color:var(--muted);font-size:14px;min-width:54px}
.result.good .r-value{color:var(--ok)}
.result.bad .r-value{color:var(--warn)}
.actions{margin:16px 0 4px;display:flex;gap:10px}
button{cursor:pointer;border:none;border-radius:8px;padding:10px 18px;font-size:15px;font-weight:700}
button.primary{background:var(--brand);color:#fff}
button.primary:hover{background:#175a49}
button.secondary{background:var(--chip);color:var(--ink)}
button.secondary:hover{background:#dbe4e7}
.note{background:#fff8ec;border:1px solid #f0d9a8;border-radius:8px;padding:10px 12px;color:#7a5a16;font-size:13.5px;margin:12px 0}
.formula{background:#f0f4f5;border-left:3px solid var(--brand2);padding:8px 12px;border-radius:0 6px 6px 0;font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:13.5px;color:#243b42;overflow-x:auto}
.site-footer{max-width:1080px;margin:0 auto;padding:18px;color:var(--muted);font-size:12.5px;border-top:1px solid var(--line)}
.site-footer p{margin:0}
.sub-note{color:var(--muted);font-size:13px}
.tabbar{display:flex;gap:6px;flex-wrap:wrap;margin:10px 0}
.tabbar button{padding:7px 12px;font-size:13.5px;background:var(--chip);color:var(--ink);font-weight:600}
.tabbar button.active{background:var(--brand);color:#fff}
@media (max-width:560px){
  .field input,.field select{max-width:100%}
  .card-grid{grid-template-columns:1fr 1fr}
}