Dynamic Css

Hi,
I have project with CMS application, in my project my project guide inform me that we have to generate the CSS dynamically, means at run if admin is login then if he select the pink color so based on that all the header,sidebar,footer and text will change, means in this task the color which admin will select it will work as input type and then based on that we have to generate css dynamic and affect to my thems.

Thanks
Harshida