function setCSSStyles()
{                
    if(screen.availWidth <= 800)
    {

        document.write('<link rel="stylesheet" type="text/css" href="fileadmin/rep/style/main800.css" />');
    }
    else
    {
        document.write('<link rel="stylesheet" type="text/css" href="fileadmin/rep/style/main.css" />');
    } 

}