A PIE method of clearing floats utility class and mixin.
.float-clear::after { content: "."; display: block; clear: both; height: 0; line-height: 0; overflow: hidden; visibility: hidden; }
.columns { @include float-clear; }
Content
<div> <div class="float-clear"> <div style="float: left; margin-right: 20px;">float:left</div> <div style="float: left; margin-right: 20px;">float:left</div> <div style="float: left; margin-right: 20px;">float:left</div> </div> <p>Content</p><!-- paragraph isn't floating --> </div>