style.css

body {
    background-image: url("./images/background.png");
    background-size: cover;
    color: white;
    font-family: Bodoni, "Bodoni MT", "Didot", "Didot LT STD", "Hoefler Text", Garamond, "Times New Roman", serif;
}

#logo {
    display: flex;
    justify-content: center;
}

#logo img {
    max-height: 2.4em;
    margin: .3em .3em .3em .3em;
}

#made_by {
    display: flex;
    justify-content: center;
}

#tries_title {
    display: flex;
    justify-content: center;
    font-size: 1.5em;
    font-weight: bolder;
    margin-bottom: .5em;
    margin-top: .8em;
}

.options {
    display: flex;
    justify-content: center;
    margin-bottom: 1em;
}

.options button {
    font-family: Bodoni, "Bodoni MT";
    padding: 10px 14px;
    font-size: 13px;
    border-radius: 15px;
    background-color: #ffffff56;
    color: #ffffff;
    border-style: solid;
    border-color: #ffffff;
    font-weight: bold;
}

.options button:hover {
    cursor: pointer;
    transform: scale(.95);
    background-color: #181818;
    color: #ffffff;
    border-color: #ffffff;
    transition: all 0.2s ease-in-out;
}

.cards-grid {
    display: grid;
    justify-content: center;
    grid-gap: 16px;
    grid-template-columns: repeat(6, 8em);
    grid-template-rows: repeat(4, 8em);
}

.card {
    height: 8em;
    width: 8em;
    border-radius: 10px;
    background-color: white;
    position: relative;
    transform-style: preserve-3d;
    transition: all 0.5s ease-in-out;
}

.card:hover {
    cursor: pointer;
    transform: scale(1.05);
    transition: all 0.2s ease-in-out;
}

.front-card img {
    width: 60px;
    height: 60px;
}

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

.card.flipped img {
    max-width: 8em;
    max-height: 8em;
}

.front, .back {
    backface-visibility: hidden;
    position: absolute;
    border-radius: 10px;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
}

.card .front {
    display: flex;
    justify-content: center;
    align-items: center;
    transform: rotateY(180deg);
}

.card .front img {
    max-width: 8em;
    max-height: 8em;
}

.card .back {
    background-image: url("./images/back_card.png");
            background-position: center;
            background-size: cover;
            backface-visibility: hidden;
    }

#space {
    padding: 5px;
}