.ct-col {
    width: 100%;
    float: left;
    box-sizing: border-box;
    @for $i from 1 to 24 {
        &.ct-col-#{$i} {
            width: percentage($i/24) ;
            box-sizing: border-box;
        }
    }
}
[class*=ct-col-] {
    float: left;
    box-sizing: border-box;
}