How can I change default textarea styles?

Sorry for my Eng,
I need to synchronize styles of textarea with my site styles.
How can I do this?
For example I need default <p> to be some smaller and have another color.
Setting into the config.js:

CKEDITOR.addStylesSet( 'my_styles',
[       
 { name : '', element : 'p', styles : { 'color' : '#62AC00' , 'font-family' : 'Arial' , 'font-size' : '8px' } }
]);

That setting inside function( config ):

config.stylesCombo_stylesSet = 'my_styles';

And it doesn't work!
CKEditor textarea keeps displying tag <p> its own default way.

Point the finger at mistake, PLZ!