#container {
    width: 90%;
    max-width: 350px;
    min-width: 200px;
    margin: 1rem auto;
    box-sizing: border-box;
    padding: 1rem;
}

#board {
    --columns: 0;
    display: grid;
    grid-template-columns:auto repeat(var(--columns), 1fr);
}

.tile {
    aspect-ratio: 1/1;
    background-color: white;
    outline: 2px black solid;
    &.mark { background-color: gray; }
    &.right { background-color: green; }
    &.wrong { background-color: red; }
}

.hint {
    display: grid;
    align-items: center;
    &.top { margin-bottom: 1rem; text-align: center; }
    &.left { margin-right: 1rem; text-align: right; }
}