Example CSS for vb4 - put it in your additional.css
Will work for vb3 too.
Code:
.stg_table {border-color:#000; border-width: 2px; padding: 2px; background-color:#250517;}
.stg_table td {border-color:#000; border-width: 2px; }
.stg_table .alt1 {border-color:#000; border-width: 2px; background-color:#111111; }
.stg_table .alt2 {border-color:#000; border-width: 2px; background-color:#333333; }
Enjoy.