if (is.win) 
  document.write("<LINK REL=stylesheet TYPE=text/css HREF=/gvu/style/main-pc.css TITLE=gvuhome>")
else 
  if (is.mac) 
    document.write("<LINK REL=stylesheet TYPE=text/css HREF=/gvu/style/main-mac.css TITLE=gvuhome>")
  else
    if (is.unix) 
      document.write("<LINK REL=stylesheet TYPE=text/css HREF=/gvu/style/main-unix.css TITLE=gvuhome>")
    else 
      document.write("<LINK REL=stylesheet TYPE=text/css HREF=/gvu/style/main.css TITLE=gvuhome>")