jQuery自定义滚动条样式插件mCustomScrollbar 兼容IE7的方法

Here is what is in my ie7.css:
.mCSB_scrollTools .mCSB_draggerRail{width:2px;height:100%;margin:0 0 0 -1px;-webkit-border-radius:10px;-moz-border-radius:10px;border-radius:10px;left: 50%;position: absolute;}.mCSB_scrollTools .mCSB_buttonDown{top: auto;bottom: 0;left: 0;margin: 0;position: absolute;width: 100%;}