Font color and size

I have been trying to change to color and size of the headlines on our articles on the iphone template. We use h4 for the main headline and h2 for our 2nd headline.
But I am really having trouble finding out where the css file is to change this. I have tried the theme.css and theme.min.css in both template/iphone/themes/jqt and template/iphone/themes/apple but any change just doesn't show.
I have Firebug bug again this won't tell me where the color is coming from.
If anyone know where the css is that holds all the text styling or why when I make changes nothing is happening then please let me know.
my site is www.iphone.proficiencypost.com

Many thanks Wicko

templates/mobile_iphone/css/mj_iphone.css ?

Yes I have made changes to this css also and none of the color changes are appearing. I turned off gzip compression in the joomla modile in case it was still holding a compressed version of the css file.
Would there be an override that is stopping the css from working?