You appear to be using a Zen Cart version of 1.3.x but have pasted some old css code into your stylesheet.css that addresses tables that do appear to exist.
This is starting at:
Code:
/*HEADER CSS*/
TABLE.header {
background-image: url('../images/header_bg.jpg');
background-repeat: repeat-x;
background-color: #708190;
border-right: 1px solid #9a9a9a;
border-left: 1px solid #9a9a9a;
border-bottom: 1px solid #9a9a9a
}
This and the subsequent code that addresses tables does not appear to be controlling anything. check your template_default stylesheet and compare.
Start there and then the other things might clear up??