editing the nof_shoppro.css file

When I preview my eshop in a browser, the ecommerce fonts and colours are 
different to what I've chosen and stick out like a sore thumb. NOF help says 
I need to


"To change/edit the e-commerce fonts you will need to edit the 
nof_shoppro.css file"

Can someone please tell me how to do this. I've looked at the html code and 
it's a mystery to me! Can't see how I can change the font type and colour.

I also don't like their black arrows on the browser preview page, which is 
built into the ecommerce shop (same as the fonts). I assume I need to change 
these the same way. Any help on this also greatly appreciated.

Thanks in advance.

Lorraine