styles.css

@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@100;300;400;500;700&display=swap');

body {
    background-color: #EEF9BF;
}

.top {
    display: flex;
    justify-content: center;
    align-items: center;
}

h1 {
    font-family: 'Roboto', sans-serif;
    font-weight: 700;
    color: #75b79e;
    font-size: 56px;
    text-align: center;
    margin: 40px auto;
}

.cards-container{
    display: flex;
    width: 900px;
    justify-content: center;
    margin: 0 auto;
    flex-wrap: wrap;
}

.card{
    width: 117px;
    height: 146px;
    background-color: #A7E9AF;
    border: 1px solid #99CEA8;
    margin: 17px;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    transition: all .5s;
}

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

.back-img {
    width: 100px;
}

.front-img {
    width: 80px;
    position: absolute;
}

.hidden {
    display: none;
    z-index: -1;
}

@media(max-width: 414px){

    .top {
        width: 90%;
    }

    .cards-container{
        width: 90%;
        flex-direction: column;
        align-items: center;
    }
}