CSS error?

I enabled simplemarket theme for marketpress, set the "presentation" to custom theme. And went to add a product.

I noticed the 'buy now' button isn't there. Upon investigation, it is there, but it's set to WHITE. Simplemarket is an all white theme by default. Is this a glaring error or is there something else going on here?

a.mp_link_addcart, a.mp_link_buynow {
float: right;
font-weight: bold;
padding: 0.5em 0.8em;
text-decoration: none;
color: white!important;}