Anchor offset for sites with Fixed header

We have added the helper class of .anchor for sites that use fixed header navigation and also have the anchors appear below the header.

.anchor {
	&:before {
		content: '';
		display: block;
		padding-top: 100px; 
		margin-top: -100px;

the offsite can be set to be the same as the header hight and also use media queries if required.