CSS Grid - Piece of cake

This is my CSS Grid implementation.

To study how it works, check it out the grid.css file. Super easy to understand.

We have basically:

• a .group class just to clear the floats;
• a div[class^='column-'] selector to get all div who starts with column-. I set the gutter using padding + box sizing;
• first-child and last-child to remove respective paddings at the begin and end;
• a total of 12 columns that you can mixin to make your layout. Here, i'm using calc to get the sizes;
• check it out the code inside class cake-filling in index.html file to see a example of usage.

Check it out the demo here, http://fernandoperigolo.github.io/piece-cake-grid/