Color navigation

Hello everybody,

I have a small site and would like to divide it in different sections.
When visitors click to certain links they come in a different section of the site.
All colors of the site need then to be adapted.

Section A > Logo and link color in red
Section B > Logo and link color in blue
Section C > Logo and link color in green
Section D > …

My site is made in php and page are based like " index.php?page=welcome" , “_index.php?page=contact”

I thought to do this with a cookie, php and for each color a different css file.
Any other suggestions because when people come from google to a random page this solutions isnt’t really working