Thanks for making this widget - very useful.
I was hoping I could make some suggestions to add some more css support to the settings panel. I really like that you've added the ability to change colors and such.
I changed the width to appear as auto because the default size was much too small for my right column.
I also changed the width of the submission fields to by naming the pixel width instead of "auto" ... my concern with doing that is that different browsers might render that differently, though so far that doesn't appear to be a problem.
And, I centered the "Submit" button using margin-left.
I don't mind making the changes - I was just thinking ahead to when an update rolls out I'll have to put the changes into the widget code again (if I don't forget). :)