.dd {
        position: relative;
        display: block;
        margin: 0;
        padding: 0;
        /*max-width: 600px;*/
        list-style: none;
        font-size: 13px;
        line-height: 20px;
    }

    .dd-list {
        display: block;
        position: relative;
        margin: 0;
        padding: 0;
        list-style: none;
    }

    .dd-list .dd-list {
        padding-left: 30px;
    }

    .dd-collapsed .dd-list {
        display: none;
    }

    .dd-item,
    .dd-empty,
    .dd-placeholder {
        display: block;
        position: relative;
        margin: 0;
        padding: 0;
        min-height: 20px;
        font-size: 13px;
        line-height: 20px;
    }

    .dd-handle {
        display: block;
        height: 35px;
        margin: 5px 0;
        padding: 5px 10px;
        color: #333;
        text-decoration: none;
        font-weight: bold;
        border: 1px solid #ccc;
        background: #fafafa;
        background: -webkit-linear-gradient(top, #fafafa 0%, #eee 100%);
        background: -moz-linear-gradient(top, #fafafa 0%, #eee 100%);
        background: linear-gradient(top, #fafafa 0%, #eee 100%);
        -webkit-border-radius: 3px;
        border-radius: 3px;
        box-sizing: border-box;
        -moz-box-sizing: border-box;
    }

    .dd-handle:hover {
        color: #2ea8e5;
        background: #fff;
    }

    .dd-item > button {
        display: block;
        position: relative;
        cursor: pointer;
        float: left;
        width: 25px;
        height: 20px;
        margin: 5px 0;
        padding: 0;
        text-indent: 100%;
        white-space: nowrap;
        overflow: hidden;
        border: 0;
        background: transparent;
        font-size: 12px;
        line-height: 1;
        text-align: center;
        font-weight: bold;
    }

    .dd-item > button:before {
        content: '+';
        display: block;
        position: absolute;
        width: 100%;
        text-align: center;
        text-indent: 0;
    }

    .dd-item > button[data-action="collapse"]:before {
        content: '-';
    }

    .dd-placeholder,
    .dd-empty {
        margin: 5px 0;
        padding: 0;
        min-height: 30px;
        background: #f2fbff;
        border: 1px dashed #b6bcbf;
        box-sizing: border-box;
        -moz-box-sizing: border-box;
    }

    .dd-empty {
        border: 1px dashed #bbb;
        min-height: 100px;
        background-color: #e5e5e5;
        background-image: -webkit-linear-gradient(45deg, #fff 25%, transparent 25%, transparent 75%, #fff 75%, #fff), -webkit-linear-gradient(45deg, #fff 25%, transparent 25%, transparent 75%, #fff 75%, #fff);
        background-image: -moz-linear-gradient(45deg, #fff 25%, transparent 25%, transparent 75%, #fff 75%, #fff), -moz-linear-gradient(45deg, #fff 25%, transparent 25%, transparent 75%, #fff 75%, #fff);
        background-image: linear-gradient(45deg, #fff 25%, transparent 25%, transparent 75%, #fff 75%, #fff), linear-gradient(45deg, #fff 25%, transparent 25%, transparent 75%, #fff 75%, #fff);
        background-size: 60px 60px;
        background-position: 0 0, 30px 30px;
    }

    .dd-dragel {
        position: absolute;
        pointer-events: none;
        z-index: 9999;
    }

    .dd-dragel > .dd-item .dd-handle {
        margin-top: 0;
    }

    .dd-dragel .dd-handle {
        -webkit-box-shadow: 2px 4px 6px 0 rgba(0,0,0,.1);
        box-shadow: 2px 4px 6px 0 rgba(0,0,0,.1);
    }