Stylesheet style.css rtl.css

Hi,

My theme has two style sheets listed under Stylesheet, and only one had content to edit. The rtl.css is editable. BUT, the edits are not showing up. I saved the updates, cleared cache on my browser window, and still NOT updating. Help please. 🙁

Stylesheet
(style.css)
RTL Stylesheet
(rtl.css)

This is the url: http://nutheadproductions.com/wp/

I simply want to change the navigation bar button colours. I changed every colour code from the default blue to a lighter blue, #96B7C6, but not working. :S

Thank you for your help!
Shirley