Three Columns on a web page!

I'm a section that is 30% wide, floated left, and has a 1.5% margin on the left and right!

Things to remember:

Use the box-sizing:border-box; property on your columns!
If you want the entire page to use border box you can use the universal selector:
* {box-sizing: border-box;}
The width + margin of all three columns must total less than 100%!