A simple button, styled with different
box-shadows for a 3D-look. The first value of the
box-shadow is to give height / depth to the button and the second value is to give shadow to it. There is nothing else in this buttons except this clever use of box shadows. When clicked, the size of the box shadows is decreased to lower the depth and make it look like its being pressed.
Also, transition effects are used to add a little animation on the push effect. It works well in Chrome, Safari, Firefox and Opera.