How do disabled the drop down in CSS (with out disabled option)?

hai,
i'm using for . it's working fine.
The same CSS i can't use in dropdown like

...
..

If i give disabled, it won't allow to select. but the text color i want whatever in the Det_NoneditForm.

Here, i can select option form the drop down. But i want don't allow to pick from the drop down.

The CSS is:
Det_NoneditForm { font-family: Tahoma; font-size: xx-small; color: #333333; border: 1px #CCCCCC solid; border-color: #0099CC #0099CC #0099CC #0099CC ; background-color: #DBDBDB}

please give solution.
Thanks
by
shiyam