:root{font-family:system-ui,-apple-system,Segoe UI,Roboto,Helvetica Neue,Arial;color:#111;padding:12px}.container{max-width:640px;margin:28px auto}h1{font-size:1.6rem;margin-bottom:8px}.form{display:grid;gap:8px;margin-bottom:12px}label{display:flex;justify-content:space-between;align-items:center;gap:8px}input{flex:1;padding:8px;border-radius:6px;border:1px solid #ddd}button{padding:10px 14px;border-radius:8px;border:none;cursor:pointer;background:#0b74de;color:#fff}.output{margin-top:12px}.card{padding:12px;border-radius:8px;box-shadow:0 6px 20px #0b74de14;background:#fff}.err{color:#b00020}.foot{margin-top:18px;color:#666;font-size:.85rem}