how can change the data in css files ???? (in winform application using .net)

Question

how can i change the data in multiple css files like i have data.css , product.css and manager.css . i want that when i enter the value of any tag like (border right) in data.css file then it will implemented that code in another css like prouct.css and manager.css . i want that file should be automaticaly generated from the data.css.  The data should be autmaticaly changes between product.css and manager.css when i update the value in data.css.

 also i want if i have multiple css file then i want that my webpage will implemented on the IE8,IE9 , firefox and google chrome with in one code i do not change the every css files 1 file is for IE8, 1 file is for IE9 and so on ... i code will be same for every IE8,IE9 , firefox and google chrome  i dont want to change the code for every webpage 

so anybody tell me how can i do this ??????????

data.css

body

{

    border-right: thin groove;

    border-top: thin groove;

    border-left: thin groove;

    color: blue;

    border-bottom: thin groove;

    font-family: Tahoma, Trebuchet MS;

}

product.css

h1

{

color:red;

background-color:Yellow;

font-family:Comic Sans MS;

}