Changing Site Header For Portfolio Pages

Site URL: https://www.robin-lyons.com/other

Hello,

I'm wanting to make it so when you click through from any of the pages on https://www.robin-lyons.com/other (password is 'peach') the header changes to be a solid white with text in black on the page you land on. I have attached a reference image to show how I want it to look. I'm wanting to do this without effecting how the header is across the rest of the site.

If helpful, the page that you are clicking through from is a 'portfolio' page and the links go to one of its sub pages. 

Any help would be most appreciated.

Thanks,

Robin.

Solved it. Heres how:

body#item-6151b5d0ee776231ddd14c5a #header{background-color: #FFF !important;}
body#item-6151b5d0ee776231ddd14c5a 
#header a {color: #111 !important;}