Changing colors on loading page.

I'm in trouble on trying to change the color on the page that appears when the site is loading.
I'm not so skilled with css but if i edit with notepad++ the K2.css file (identified using Firebug) and sobsitute the original #7484ff with another one, nothing changes even if I purge browser and site cache.
Obviously I'm making a mistake....... I also tried to remove the same color #7484ff from "what we do" button but I wasn't able to do it.

Old template and old question and old answer: https://www.gavick.com/documentation/jo ... creativity

Ops, sorry. Every search I've done gave me so many posts that was impossible to find one that match my doubt. Thank You!
P.s. finally I was able to find the right css and I preferred to modify it using the editor, without overridess.