Button color and sidebar

Hi! I don't know much about css, so I thought I'd ask this here instead of losing my mind trying to figure it out. Is there any way to change to color of the "submit" button in a form (example http://paniikki.net/paniikki/palaute/)? Should I just choose a different color scheme? And another thing: how can I add some padding to the side bar? Now it has to be the same color as the background, otherwise it looks really stupid when all the text is too close to the edge. I'd really appreciate any advice :)