Quickview is by default disabled in the REVO template and doesn't have any special styling set for it.
If you enable it, you may need to change the styling for the "button" used for the quickview function at:
=> btn btn-height-66
will increase the height for the button to 66; the appearance will be like a square button
=> btn btn-height-66 btn-rounded
this will add rounded corners to the square button above
=> btn btn-height-66 btn-round
this will create a round button
Keep in mind that not all combinations will look fine, but as you see you can change the appearance of the buttons a lot with some simple changes.