Where do I find CSS style for the SELECTed element in the Attribute drop down box?

[Milosh]

I want to enlarge the font in the SELECT field but I only managed to influance the general 'option' elements but not the SELECTED current element.

I am checking the source code and using inspect element feature from the tools in Firefox and I managed to find the OPTION element not the active selected one.

 

Any idea in which css file would that be? and what is the class name?

 

As you can see below, the active element still has the original smaller font. Thanks for help.