/* 滚动条样式 */
::-webkit-scrollbar
width 8px
height 8px
::-webkit-scrollbar-thumb
border-radius 5px
-webkit-box-shadow inset 0 0 5px rgba(0,0,0,0.2)
background rgba(0,0,0,0.2)
::-webkit-scrollbar-track
-webkit-box-shadow inset 0 0 5px rgba(0,0,0,0.2)
border-radius 0
background rgba(0,0,0,0.1)
效果：
