body { font-family: system-ui, sans-serif; background:#f4f6f8; display:flex;
       min-height:100vh; align-items:center; justify-content:center; margin:0; }
.card { background:#fff; padding:2rem; border-radius:12px;
        box-shadow:0 4px 20px rgba(0,0,0,.08); width:300px; }
h1 { font-size:1.2rem; margin:0 0 1rem; }
input { width:100%; padding:.6rem; box-sizing:border-box; border:1px solid #ccc;
        border-radius:8px; font-size:1rem; }
button { width:100%; margin-top:1rem; padding:.6rem; border:0; border-radius:8px;
         background:#2563eb; color:#fff; font-size:1rem; cursor:pointer; }
.err { color:#b91c1c; font-size:.9rem; margin-top:.6rem; }