body{background:#000;color:#fff;font:20px/1.5 -apple-system,system-ui,sans-serif;margin:0;padding:2rem}
main{max-width:40rem;margin:auto}
input,button,select{font:inherit;color:#fff;background:#111;border:2px solid #fff;padding:.4rem .6rem;margin:.25rem 0}
button{background:#ffd400;color:#000;font-weight:700;cursor:pointer}
:focus{outline:4px solid #00e5ff;outline-offset:2px}
#err{color:#ff8080;font-weight:700}