Circle Buttons in CSS

This is just a small trick in css to create circle like buttons.
To achieve this just put the width and height equal to each other and equal to the css border radius of a button.
If the button is 20 by 20 px than to make it look like a circle in JavaFX CSS:

.circleButton
{
    -fx-border-radius: 20;
}

I believe this also applies to web CSS3 but I haven’t tested it.
The following picture illustrates a zoom panel that I’ve done. The two buttons for zoom in and zoom out look circle like.