Bootstrap 3 - Column top margin on smaller screens

Question

I have a row with X possible columns.

<div class="container">
    <div class="row">
        <div class="col-lg-3 col-sm-4 col-xs-6">content</div>
        <div class="col-lg-3 col-sm-4 col-xs-6">content</div>
        <div class="col-lg-3 col-sm-4 col-xs-6">content</div>
        <div class="col-lg-3 col-sm-4 col-xs-6">content</div>
        <div class="col-lg-3 col-sm-4 col-xs-6">content</div>
        <div class="col-lg-3 col-sm-4 col-xs-6">content</div>
        <!-- ... and so on ... -->
    </div>
</div>

Now I would like to add margin-top:20px to all small screen columns and the same margin for big screen columns, if there are more than 4 as that would cause two "rows" to be shown and would therefore require some space between.

Is that somehow possible with only the use of CSS?

Answer 1

You can use a media query for whenever you want the top margin..

@media (max-width: 767px) {
    .col-xs-6 {
        margin-top:20px;
    }
}

http://www.bootply.com/126007

P.S. - There is nothing wrong with having the total of .col-* in a .row exceeding 12 (ie: http://getbootstrap.com/css/#grid-example-mixed). It simply causes a wrap. There are several examples in the docs that use this technique. It's generally not ideal for nested rows.

Answer 2

I needed something similar and following is the solution I came up with. Documenting it for future readers (and myself)

$res-list: (xs: (0px, 767px), sm: (768px, 991px), md: (992px, 1199px), lg: (1200px, 9999px));
$dir-list: (t: top, r: right, b: bottom, l: left);

@for $r from 1 through 10{
  @each $res-abbr, $res-vals in $res-list{
    @media (min-width: nth($res-vals, 1)) and (max-width: nth($res-vals, 2)) {
      @each $dir-abbr, $dir-name in $dir-list{
        $x: $r * 5;
        .m#{$dir-abbr}-#{$res-abbr}-#{$x}{
          margin-#{$dir-name}: #{$x}px;
        }
        .m#{$dir-abbr}-#{$res-abbr}-#{$r}p{
          margin-#{$dir-name}: #{$r}unquote('%');
        }
      }
    }
  }
}

This SASS code generates classes along the lines of following

@media (min-width: 0px) and (max-width: 767px) {
    .mt-xs-5 { margin-top: 5px; }
    .mt-xs-1p { margin-top: 1%; }
    .mr-xs-5 { margin-right: 5px; }
    .mr-xs-1p { margin-right: 1%; }
    .mb-xs-5 { margin-bottom: 5px; }
    .mb-xs-1p { margin-bottom: 1%; }
    .ml-xs-5 { margin-left: 5px; }
    .ml-xs-1p { margin-left: 1%; } 
}

So the content editor can use .mt-xs-10 to apply margin-top: 10px to given element on extra-small screen.

I hope it helps somebody.