$row-prefix:#{$css-prefix}row;
$col-prefix:#{$css-prefix}col;
@mixin row($gutter: $grid-gutter-width){
    position: relative;
    margin-left: $gutter / 2;
    margin-right: $gutter / 2;
    height: auto;
    @include clearfix;
}
@mixin float-grid($gutter: $grid-gutter-width){
    position: relative;
    margin-left: $gutter / -2;
    margin-right: $gutter / -2;
    height: auto;
    @include clearfix;
}
@mixin grid{
    @for $i from 1 through 24 {
        .#{$col-prefix}-span-#{$i} {
            display: block;
            float: left;
            width: percentage(($i / $grid-columns));
        }
    }
}