Box Shadow

The structure of Box shadow is:

box-shadow: horizontal offset vertical offset blur spread color inset,
            horizontal offset vertical offset blur spread color inset,
                     .....                             .....
            horizontal offset vertical offset blur spread color inset;

If you want to read more, go to the official specification at W3: http://www.w3.org/TR/css3-background/#the-box-shadow. A good description you can find on https://developer.mozilla.org/en-US/docs/CSS/box-shadow. You can also look on http://www.w3schools.com/cssref/css3_pr_box-shadow.asp.

Which browsers do support this, see "Can I use CSS3 Box-shadow?" on www.caniuse.com. You can test for support with javascript:

document.getElementsByTagName("body")[0].style.boxShadow !== undefined

This test is true, if box shadow is supported.

You can see the instruction video at youtube by clicking on this text here. To see how it works: Play around!