1.6 Change Colour Red/Blue/White strip form top of contact form

[DonnaTB]

Please could someone tell me how to rchange the red, blue and white strip from the top of the contact page to a different colour, say silver and white?

I have looked in the CSS folder and can't see the colours for the red, blue etc to change? I must be looking in the wrong place?

Thank you 

[JBW]

It's an background-image, you see it in line 15

[DonnaTB]

Thank you, I never thought to look for it as an image! Thank you very much