Dynamically Load CSS File ( Styles ) from Database in ASP.Net

i am working on project which have three module admin, jobseeker and employee.

i wnat to provide authroty to admin who change the css or look and feel of the website.

i have used 3 seprate master page and one two css file. named style1 and style2.

i want to replace the css by clicking on button or choosing the dropdown.

like if admin choose style1 then style1 is permanently aplyed to website.

if admin choose style2 then then style2 is permanently aplyed to website.

admin can also change style accoring to module name. like he or she choose employee module and style 2 so that particular style is applyed to employee module.

plese help me.