* {
    box-sizing: border-box;
}

body {
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
}

.bingo__board {
    display: flex;
    flex-wrap: wrap;
    border: 1px solid black;
}

.bingo__title {
    font-size: 2em;
    text-align: center;
    width: 100%;
}

.bingo__card {
    border: 1px solid black;
    flex: 1 0 20%;
    height: 15vh;
    font-size: 3vmin;
    padding: 0.2em;
    cursor: pointer;
}

.bingo__card--done {
    text-decoration: line-through;
}

.bingo__overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    color: white;
    font-size: 5vmin;
    display: none;
}

.bingo__overlay img {
    width: 100%;
    height: 100%;
}