Basics of CSS for rounded corners here.
Update: In order to render my textbox consistently across iOS/BlackBerry/Android, the only successful way was NOT to use size=# or =#em or =#%, but to set the width of the input to be width: ###px . When I do that (inline or in CSS) it wrecks the rounded corners effect.
I have determined that setting the width attribute is what breaks the corners.
My question: Is there another way to set the width attribute? I’m open to another idea of how I can render the size of the textbox consistently cross-platform?
I solved my issue by decreasing the radius of the rounded corners (see comments)