clearfix.css

/* Clear Floated Elements
----------------------------------------------------------------------------------------------------*/

/* http://sonspring.com/journal/clearing-floats */

.clear {
	clear: both;
	display: block;
	overflow: hidden;
	visibility: hidden;
	width: 0;
	height: 0;
}

/* http://perishablepress.com/press/2008/02/05/lessons-learned-concerning-the-clearfix-css-hack */

.clearfix:after {
	clear: both;
	content: ' ';
	display: block;
	font-size: 0;
	line-height: 0;
	visibility: hidden;
	width: 0;
	height: 0;
}

.clearfix {
	display: inline-block;
}

* html .clearfix {
	height: 1%;
}

.clearfix {
	display: block;
}

clearfix.sass

.u-clearfix {
    *zoom: 1;
    &:before, &:after {
        display: table;
        content: " "
    }
    &:after {
        clear: both;
    }
}