styles.css

:root {
    --cell-size: 100px;
    --mark-size:calc(var(--cell-size) * 0.9)
}


.container {
    height: 100vh;
    width: 100vw;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: grey;
}

.board {
    width: calc(var(--cell-size) * 7.5);
    height: calc(var(--cell-size) * 6.5);
    background-color: darkblue;
    display: grid;
    justify-content: center;
    align-content: center;
    align-items: center;
    grid-template-columns: repeat(7, auto);
    border-radius: 25px;
}


.cell {
    border-radius: 50%;
    width: var(--cell-size);
    height: var(--cell-size);
    border: 2px solid blue;
    background-color: grey;
    margin: 1px;
}

.cell.red {
    background-color: red;


}

.cell.yellow {
    background-color: yellow;
}

.board.red .cell:hover {
    background-color: lightcoral;
}

.board.yellow .cell:hover {
    background-color: lightyellow;
}



.winning-message {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, .9);
    
    justify-content: center;
    align-items: center;
    color: white;
    font-size: 5rem;
    flex-direction: column;
}
.winning-message button {
    font-size: 3rem;
    background-color: white;
    border: 1px solid black;
    padding: .25rem .5rem;
    cursor: pointer;
}

.winning-message button:hover {
    background-color: black;
    color: white;
    border-color: white;
}

.winning-message.show {
    display: flex;

}

.winning-message.show {
    display: flex;
}