*{box-sizing:border-box}body{margin:0;font:16px/1.5 system-ui,-apple-system,"Segoe UI",sans-serif;
background:#f6f5f2;color:#1d1d1b}main{max-width:520px;margin:0 auto;padding:40px 16px}
h1{font-size:1.5rem}.carte{background:#fff;border:1px solid #e3e1db;border-radius:12px;padding:18px}
label{display:block;font-weight:600;margin:12px 0 6px}input{width:100%;font:18px ui-monospace,Consolas,monospace;
padding:10px;border:1px solid #c9c6bd;border-radius:8px;letter-spacing:.04em}button{margin-top:14px;
width:100%;background:#1f4e79;color:#fff;border:0;border-radius:8px;padding:12px;font:inherit;cursor:pointer}
.petit{color:#6b6963;font-size:.9rem}.erreur{color:#9b1c1c;font-weight:600}