Dynamic Css Sheets

I'm using dynamic css sheets.What I'm currently doing is reading a normal css sheet as a text file, then using regular expression to change all the size values and outputting the resized css.Would it be faster to put a resizing function in the asp page that outputs the css, rather than using regexp to change a stylesheet? something like this
Code:
<%
Function resize(n)
resize=Int(clng(n)*(size/12))
End Function
%>
h1{height:<%=resize(20)%>px;width:<%=resize(200)%>px;}
#firstDiv{height:<%=resize(120)%>px;width:<%=resize(200)%>px;}
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