section { display: grid; gap: 4px; grid-template-columns: repeat(10, 50px); } .vertical { grid-template-rows: repeat(10,
1fr); grid-template-columns: 50px; } .row { display: contents; } button { width: 100%; height: 30px; min-width: 30px;
display: block; } button[selected] { background: green; color: white; }