Bootstrap 3 - Column top margin on smaller screens

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.

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.

This is an old post but below is a clean solution.

[class*="col-"] {
  margin-bottom: 15px;
}

This works well for some situations but it adds extra, unnecessary margin when it's not needed. To solve this, we can create a new css class that applies top margin to columns when they get stacked. I create a class named .row-grid

.row.row-grid [class*="col-"] + [class*="col-"] {
  margin-top: 15px;
}

@media (min-width: 1200px) {
  .row.row-grid [class*="col-lg-"] + [class*="col-lg-"] {
    margin-top: 0;
  }
}
@media (min-width: 992px) {
  .row.row-grid [class*="col-md-"] + [class*="col-md-"] {
    margin-top: 0;
  }
}
@media (min-width: 768px) {
  .row.row-grid [class*="col-sm-"] + [class*="col-sm-"] {
    margin-top: 0;
  }
}

I use this simple and clean solution:

.row { margin-top: -15px; }
.row > div { margin-top: 15px; }

In that manner, every <div class='col-*-*'> has 15px margin on top, except those on the first row (or, on mobile, except the one on the top).