clearfix()
    zoom: 1
    &:before,
    &:after
        content: ""
        display: table
    &:after
        clear: both
        visibility: hidden
        font-size: 0
        height: 0


// menu清除浮动，不需要隐藏
menu-clearfix()
    zoom: 1
    &:before,
    &:after
        content: ""
        display: table
    &:after
        clear: both