.pdf-box {
    display: grid;
    grid-template-columns: 1fr;
    column-gap: 20px;
    row-gap: 20px;
    padding: 25px;
}

.pdf-box div {
    padding: 20px;
    background: #f0f0f0;
    color: #c00;
    font-weight: 600;
    text-align: center;
    cursor: pointer;
}

.pdf-result {
    display: none;
    padding: 20px;
}

@media only screen and (min-width: 999px) {

    .pdf-box {
        grid-template-columns: 1fr 1fr;
    }

}