/// Add clearfix to a class
/// @param {boolean} $important - make properties `!important`.
///
@mixin clearfix($important: false) {
    $important: if($important, '!important', '');
    *zoom: 1 #{$important};

    &:before,
    &:after {
        content: ' ';
        display: table #{$important};
    }
    &:after {
        clear: both #{$important};
        width: 0 #{$important};
        height: 0 #{$important};
    }
}