*{box-sizing:border-box}body{margin:0;background:#f6f4f1;color:#222;font:16px/1.5 system-ui,sans-serif}
.rsvp-card{max-width:540px;margin:8vh auto;padding:32px;background:white;border-radius:18px;box-shadow:0 10px 40px #00000012}
h1{font-size:1.9rem}label{display:block;margin:18px 0}input[type=number]{display:block;width:100%;padding:12px;margin-top:8px}
button{background:#202020;color:white;border:0;border-radius:8px;padding:14px 24px;cursor:pointer}
@media(max-width:600px){.rsvp-card{margin:16px;padding:24px}}