Customizing contact form submit button

Hello,
On this page: http://yourtechadvisors.com/contact
There is a submit button at the bottom, I would like to do two things to it.
1. Put a black box around the button, and have white text.
2. On hover, I would like to use this color. #ff0000
Can this be accomplished? Support access is open.

Thanks for your wonderful support!!