I saw this question and had to stop to give the correct answer, and relieved the pain that I went over a year ago trying to find a standard way to resolve CSS formatting conflicts with JQM styles. I hope this saves you all from some of the hair that I lost, and then figured it out.
The solution lies in CSS specificity. All you have to do with any formatting conflict in JQM is to first apply the identifier to the element that you want to override JQM formatting with your own CSS.
Then, in your own CSS, indicate that the class applies to the id container.
#img_button_1 .ui-btn-inner {border: none !important;}
It is so simple.
Another important thing, and this is that the loading order of external CSS files is significant, and you will want to load your CSS after JQM CSS.
I developed a working Ryans jsFiddle example to show a slight difference with its solution, which was at least on the right track here in this post.
http://jsfiddle.net/Z8Xnx/14/
Another advantage of this approach is that you donβt have to change JQM CSS at all and leave it alone. I have successfully used this approach to resolve every JQM CSS conflict I encountered, starting with clarifying this specification requirements issue. Hope this helps everyone with the easy solution to their JQM-style puzzles.
** UPDATE **
It was noted that this method does not work with the latest version of JQM (1.3.0b1), and this is not true. I researched and discovered that this is a problem with embedding this version of JQM in jsFiddle. To prove this, I provided an example page in my own space with the same code as in the jsFiddle example. This means that in my writing, you really cannot trust anything in jsFiddle using the latest version of JQM from the options. Just a head, and you can find a working implementation in ...
jQuery Mobile CSS Override Example
Epiphany
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