Did you know that the font-weight attribute corresponds with the font style control in Photoshop? Font weight isn’t just a way to define how bold something it is. It is a way to harness the variations in professional fonts to maintain some typographic consistency between what is created in Photoshop and what you put on the web.
Here is how it all maps out:
font-weight:200; //Extra Light
font-weight:400; //Normal, Regular, Roman
font-weight:600; //Semibold, Demibold
The Photoshop Font Style toggle is where you go to map to font-weight.