carnotaurus:

The innovations that LESS brings to CSS are the foundation for a powerful new approach to constructing page layouts. That approach is the The Semantic Grid System. This new breed of CSS grid shines where the others fall short:

1. It’s semantic;
2. It can be either fixed or fluid;
3. It’s responsive;
4. It allows the number of columns, column widths and gutter widths to be modified instantly, directly in the style sheet.

I would never dream of using CSS markup like #header. To understand the reason not to do so, one must appreciate that developers target web controls using that class attribute and not ID. This is because when an ID for a control is dynamically generated server-side, the client-side ID is indeterminate.

(Source: decodering, via carnotaurus)