body { font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial; background:#f7f7fb; }
.container { max-width: 980px; margin: 40px auto; background:#fff; padding:24px; border-radius:16px; box-shadow:0 10px 30px rgba(0,0,0,.08); }
h1 { margin-top:0; }
.grid { display:grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
label { display:flex; flex-direction:column; font-size:14px; gap:6px; }
input, select { padding:8px 10px; border:1px solid #ddd; border-radius:8px; }
button { margin-top:16px; padding:10px 16px; border:0; background:#3b82f6; color:#fff; border-radius:10px; cursor:pointer; }
.result { margin-top:16px; font-size:18px; }
@media (max-width: 900px) { .grid { grid-template-columns: 1fr; } }