Robyn,
I believe the Authentic theme makes a box with a shadow around it for block quotes. Here’s the styling:
blockquote p {
margin-left: 20px;
margin-right: 20px;
-moz-box-shadow: 0px 0px 4px rgba(0,0,0,0.3);
-webkit-box-shadow: 0px 0px 4px rgba(0,0,0,0.3);
box-shadow: 0px 0px 4px rgba(0,0,0,0.3);
padding: 5px;
font-style: italic;
border: 1px solid #c0c0c0;
}
You can certainly change that either with the Custom CSS box or by editing the style.css file directly.
If you have any questions let me know,
Bill