.sudoku-stage {
    margin-top: 14px;
    padding: 14px;
    background: var(--surface);
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
}

.sudoku-board {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    border: 2px solid #252932;
    background: #252932;
    gap: 1px;
    user-select: none;
}

.sudoku-cell {
    aspect-ratio: 1;
    display: grid;
    place-items: center;
    background: #fff;
    color: #1f2933;
    font-size: 18px;
    font-weight: 750;
}

.sudoku-cell:nth-child(3n) {
    border-right: 2px solid #252932;
}

.sudoku-cell:nth-child(9n) {
    border-right: 0;
}

.sudoku-cell:nth-child(n+19):nth-child(-n+27),
.sudoku-cell:nth-child(n+46):nth-child(-n+54) {
    border-bottom: 2px solid #252932;
}

.sudoku-cell.given {
    background: #edf0f5;
}

.sudoku-cell.selected {
    background: #fff2e8;
}

.sudoku-cell.error {
    color: #fff;
    background: #f05f57;
}

.number-pad {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 8px;
    margin-top: 14px;
}

.number-pad button {
    height: 44px;
    border-radius: 12px;
    background: var(--bg);
    border: 1px solid var(--line);
    font-size: 17px;
    font-weight: 750;
}

.number-pad button:active {
    background: var(--pressed);
}