.items, .dropzone {
    min-height: 80px;
    border: 2px dashed #ccc;
    padding: 10px;
    margin: 10px;
}

.draggable-item {
    background: #eee;
    padding: 8px;
    margin: 5px;
    cursor: grab;
}

.category {
    width: 30%;
    display: inline-block;
    vertical-align: top;
}

.correct {
    background: #b7f7b7;
}

.wrong {
    background: #f7b7b7;
}