css косая граница
Less:
.block{ position:relative; &:before{ content:''; position:absolute; top:0; left:-20px; display:block; width:20px; height:100px; background:@color_white; -webkit-transform:skewX(15deg); -moz-transform:skewX(15deg); -ms-transform:skewX(15deg); -o-transform:skewX(15deg); transform:skewX(15deg); } }