Targeting Blackberry's proprietary browser with CSS alone may prove to be a challenging task.
There are a few potential solutions:
- Implement Eric Meyer's reset.css to override browser defaults
- Adjust font size, line-height, and padding in the CSS
- If the first two options don't work, consider setting a minimum height
Keep in mind that webkit declarations may not be recognized by Blackberry's browser.
Creating consistent form field rendering across various platforms can be complex, so it's best not to stress over minor differences in appearance.