=size-xs @media (max-width: 640px) & @content =size-sm @media (min-width: 641px) and (max-width: 900px) & @content =size-md @media (min-width: 901px) and (max-width: 1024px) & @content =size-lg @media (min-width: 1025px) & @content =size-xs-sm @media (max-width: 900px) & @content =size-md-lg @media (min-width: 901px) & @content .container max-width: 1200px margin: 0 auto padding: 0 40px +size-xs padding: 0 20px .container-main padding-bottom: 50px .row +clearfix display: flex position: relative margin: 0 -10px .col @extend %prevent-children-margin box-sizing: border-box float: left padding: 0 10px @for $width from 1 to 12 .col-#{$width} @extend .col width: $width / 12 * 100% .offset-#{$width} margin-left: $width / 12 * 100%