#drop_zone {
    border: 2px solid #f5f5f5;
    height: 100px;
    border-radius: 10px;
    padding: 30px;
    text-align: center;
    font-size: 16px;
    margin-bottom: 20px;
}
div#drop_zone.active {
    border: 3px dashed #ddd;
    font-size: 15px;
}