:root { font: 18px/1.5 system-ui; color-scheme: dark; background: #12151c; color: #f3f4f8; }
main { max-width: 44rem; margin: 3rem auto; padding: 1rem; }
label { display: block; margin: 1rem 0; }
input, button { font: inherit; padding: .6rem 1rem; }
button { cursor: pointer; }
button:disabled { cursor: default; }
#board { display: grid; grid-template-columns: repeat(3, 5rem); gap: .5rem; }
#board button { height: 5rem; font-size: 2rem; }
#notice { color: #ffb5a9; }
a { color: #adcaff; }
