*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}

body{
    height: 100vh;
    display: flex;
    background-color: #fdf8e2;
}

.memory-game{
    height: 640px;
    width: 640px;
    margin: auto;
    display: flex;
    flex-wrap: wrap;
}

.memory-card{
    width: calc(25% - 10px);
    height: calc(33.333% - 10px);
    margin: 5px;
    position: relative;
    transform: scale(1);

    transform-style: preserve-3d;
    transition: transform .5s;
}

.memory-card:hover{
    transform: scale(.97);
    transition: transform .2s;
}

.card-front, .card-back{
    width: 100%;
    height: 100%;
    padding: 15px;
    position: absolute;
    border-radius: 5px;
    background: #b82d26;

    backface-visibility: hidden;
}

.card-front{
    transform: rotateY(180deg);
}

.memory-card.flip{
    transform: rotateY(180deg);
}