*{box-sizing:border-box}body{margin:0;min-height:100vh;display:grid;place-items:center;font:16px/1.5 system-ui,sans-serif;background:#0f172a;color:#0f172a;padding:16px}
.carte{background:#fff;border-radius:16px;padding:28px;width:min(400px,100%);box-shadow:0 20px 50px rgba(0,0,0,.35)}h1{margin:0}.sous{color:#64748b;margin-top:0}
label{display:block;margin:12px 0;font-weight:600}input{display:block;width:100%;margin-top:4px;padding:10px;border:1px solid #cbd5e1;border-radius:10px;font:inherit}
button{width:100%;padding:11px;border:0;border-radius:10px;background:#1d4ed8;color:#fff;font:600 16px system-ui;cursor:pointer;margin-top:8px}#msg{color:#b91c1c;min-height:1.5em}