:root{color-scheme:light}*{box-sizing:border-box}body,html{margin:0;padding:0;font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial,sans-serif;background:#fff;color:#0a0a0a}.proof-shell{max-width:720px;margin:0 auto;padding:3rem 1.5rem}.proof-card{border:1px solid #e5e5e5;border-radius:8px;padding:1.25rem;margin:1rem 0}.proof-input{padding:.5rem .75rem;border:1px solid #ccc;border-radius:6px;font-size:1rem}.proof-button{padding:.5rem 1rem;border:none;border-radius:6px;background:#0a0a0a;color:#fff;font-size:1rem;cursor:pointer}.proof-button:disabled{opacity:.5;cursor:not-allowed}