Unable to change header font with CSS

Hi guys,

I was speaking with someone recently about using a custom font on the site, and with help we were able to get the body copy working but not the header. I am at a loss to why this isn’t working and was wondering if I could get some help. URL is http://www.purelearning.co

If I can provide FTP details, are you able to check where this conflict might be occurring? There are no errors and when I inspect elements using h1 or h2 the style says that the font should be DIN, yet it’s not working.

Any help would be much appreciated!