.playground section {
    display: flex;
    flex-flow: column;
    align-items: center;

    font-family: "Source Serif", serif;
}
.playground section .card-row {
    display: flex;
    flex-flow: row wrap;
    justify-content: space-evenly;
    align-items: center;
    width: 100%;
    margin-bottom: 1rem;
}
.playground section .card-row .arrow {
    display: none;
    font-size: 2.5rem;
    cursor: pointer;
    user-select: none;
    -ms-user-select: none;
    -moz-user-select: none;
    -khtml-user-select: none;
    -webkit-user-select: none;
    -webkit-touch-callout: none;
    -webkit-tap-highlight-color: transparent;
}
.playground section .card-row .arrow:focus {
    outline: none !important;
}
.playground section .card-row .arrow:hover {
    opacity: 50%;
}
.playground section .card-row .arrow:first-of-type {
    margin-right: 1rem;
}
.playground section .card-row .arrow:last-of-type {
    margin-left: 1rem;
}
.playground section .card-row .card {
    display: flex;
    flex-flow: column;
    justify-content: end;
    align-items: center;
    border: 1px solid black;
    box-shadow: 0 4px 4px 0 rgba(0,0,0,0.25);
    width: 300px;
    height: 250px;
    background-color: hsl(0 0% 66% / 1);
    background-position: center;
    background-size: contain;
    background-repeat: no-repeat;
}
.playground section .card-row .card.cover {
    background-size: cover;
}
.playground section .card-row .card.active {
    transform: scale(105%);
}
.playground section .card-row .card > span {
    background-color: rgba(0,0,0,0.75);
    color: white;
    width: 100%;
    text-align: center;
    font-size: 0.85rem;
}
.playground section .info-box {
    display: none;
    flex-flow: column;

    margin: 0.5rem;
    padding: 0.5rem 0;
    border: 1px solid black;
    border-radius: 1px 1px 1px 1px;
    background-color: #fefefe;
}
.playground section .info-box.active {
    display: flex;
}
.playground section .info-box > .title {
    display: flex;
    flex-flow: column;
    font-weight: 600;
    padding: 0 1rem;
    width: fit-content;
}
.playground section .info-box a {
    font-size: 0.8rem;
    color: blue;
    font-weight: normal;
}
.playground section .info-box a:hover {
    font-weight: 600;
}
.playground section .info-box > .content {
    padding: 0 1rem;
    font-size: 0.8rem;
}

@media screen and (max-width: 768px)
{
    .playground section .card-row {
        flex-flow: row nowrap;
        width: 90%;
    }
    .playground section .card-row .card {
        display: none;
    }
    .playground section .card-row .card.active {
        display: flex;
    }
    .playground section .card-row .arrow {
        display: flex;
    }
}