I don't know that "clase" is a good name for a class - I got confused thinking you were doing some sort of special operation there - but you can do this, providing you are careful.
If you include the css from a separate CSS file (recommended), the variable substitution will not be done and it won't work. However, you should be able to make it work if you include the CSS inline on the JSF page (not recommend, though).
More commonly, however, people usually either select from a collection of css files ("skinning") or set the class name (or style information) on the tag they which to change styles on - for example, I have a display like so:
The backing bean code is:
An IDE is no substitute for an Intelligent Developer.
Joined: Feb 16, 2011
Thanks for the answer, then for example me would like set the style x, throught back bean but I want that the next time I load the page(from any machine), it shows the styles set in my last setting session. Then I have developed it using a DDBB.
But it is very slow, ¿is no there a way to improve that?