45° edges in HTML

[Hoibard]

Me and some friends from school have a homework to make a website about a product or a cempetition. We have chosen a Razer product so our website need to look a bit like theirs.

There are some things that neither we, nor our teacher, know how to do. 

 

If you go to Razers webpage: http://www.razerzone.com/ you can see that every block has 45° angles in every conrner. How do you make these? What is the HTML and CSS code?

Razers own way of creating these are "cheating" as they just use pictures.

[Sketched360]

This might help:

http://stackoverflow.com/questions/19248443/is-it-possible-to-create-an-angled-corner-in-css