Changed Color In Header Won’t Stay

Hello,

I’m using the Tiga theme. I’m trying to change the color in my header. I’ve gone to my style.css sheet and have replaced the original background color code with the one that I am experimenting with.

I’ve uploaded the new style sheet, and when I go to look at my page while I’m signed in to the WordPress administration section, for a brief moment I see a flicker of the color I want, but almost instantly it goes back to the default.

When I look at my page just by surfing (i.e. when I’m not signed in to the admin section) I don’t even see that flicker of color.

What am I doing wrong?

Thanks!