About theme #grid-container

Hi there

If you look at: https://vpthemes.com/preview/Felicity/
you can see a little blue line at the top.

With firebug i can find :
#grid-container {
border-top-color: #6ec0f6;
border-top-style: solid;
border-top-width: 5px;
}

But i dosent show the line number in css ..
Can anybody tell me where i can find it?
I would like to change color for the line

Really hope you can help me
C yaa | Cheers

Kimo