:root{--c:#4f46e5;--bg:#f8fafc}*{box-sizing:border-box}body{margin:0;font:17px/1.6 system-ui,sans-serif;background:var(--bg);color:#0f172a}
header,main,footer{max-width:760px;margin:auto;padding:16px 20px}header a{font-weight:700;color:var(--c);text-decoration:none}
h1{font-size:2rem;line-height:1.2}.card{background:#fff;border-radius:14px;padding:20px;box-shadow:0 2px 12px #0001;margin:18px 0}
.row{display:grid;grid-template-columns:2fr 1fr 1fr auto;gap:8px;margin:8px 0}input{padding:10px;border:1px solid #cbd5e1;border-radius:8px;font-size:16px;width:100%}
button,.btn{background:var(--c);color:#fff;border:0;border-radius:8px;padding:10px 16px;font-size:16px;cursor:pointer;text-decoration:none;display:inline-block}
button.sec{background:#e2e8f0;color:#0f172a}.res{font-size:1.4rem;font-weight:700;color:var(--c);margin-top:12px}
nav a{margin-right:14px}footer{font-size:14px;color:#64748b}label{font-size:14px}.hint{font-size:13px;color:#64748b}
@media(max-width:560px){.row{grid-template-columns:1fr 1fr}.row input:first-child{grid-column:1/-1}}