#drop_zone {
    display: block;
    font-weight: bold;
    padding: 1em 0;
    margin: 1em 0;
    color: #555;
    border: 2px dashed #555;
    border-radius: 7px;
    cursor: default;
}

    #drop_zone.hover {
        color: lightblue;
        border-color: lightblue;
        border-style: solid;
        box-shadow: inset 0 3px 4px #888;
    }