:root{
  --bg:#f1f5f9; --card:#ffffff; --muted:#64748b; --accent:#0ea5e9;
}
*{box-sizing:border-box;font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial;}
body{background:var(--bg);color:#0f172a;margin:0;padding:0;line-height:1.4}
.container{max-width:980px;margin:24px auto;padding:16px}
.header{display:flex;align-items:center;justify-content:space-between;background:var(--card);padding:12px 16px;border-radius:8px;box-shadow:0 6px 18px rgba(2,6,23,0.06)}
.logo{display:flex;gap:12px;align-items:center}
.logo img{height:42px}
.nav a{margin-left:12px;color:var(--accent);text-decoration:none;font-weight:600}
.hero{background:linear-gradient(90deg,#06b6d4,#6366f1);color:#fff;padding:18px;border-radius:10px;margin-top:16px;display:flex;gap:16px;align-items:center;justify-content:space-between}
.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:12px;margin-top:16px}
.card{background:var(--card);padding:12px;border-radius:8px;box-shadow:0 6px 18px rgba(2,6,23,0.04)}
.card h3{margin:0 0 8px 0}
.footer{text-align:center;color:var(--muted);margin-top:18px;font-size:13px}
.input,textarea,select{width:100%;padding:8px;border:1px solid #e2e8f0;border-radius:6px}
.btn{display:inline-block;padding:8px 12px;background:var(--accent);color:#fff;border-radius:6px;text-decoration:none;border:none;cursor:pointer}
.small{font-size:13px;color:var(--muted)}
.row{display:flex;gap:8px;align-items:center}
.flex1{flex:1}
.result{padding:8px;border:1px solid #e2e8f0;border-radius:6px;background:#fbfdff}
.calc-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:6px;margin-top:8px}
.calc-grid button{padding:12px;border-radius:6px;border:1px solid #e6eef6;background:#f8fafc;cursor:pointer}