.board-sudoku{--board-accent:#4da8ff;--paper-bg:#fff}.sudoku-keypad{grid-template-columns:repeat(5,minmax(44px,1fr));gap:6px;width:min(100%,480px);display:grid}.sudoku-keypad>button{min-height:48px}@media (prefers-color-scheme:dark){.board-sudoku{--board-accent:#6bb8ff;--paper-bg:#1a2338}}