These properties may seem like they do the same thing, but they actually act differently.
Learn how to create a watermark background image with just CSS.
There are many ways you can specify the font size in CSS - font units like ems, ex, pixels, and points are all available for you to design your pages.
Deciding on a filename for your CSS style sheet is important so that you don't forget what the document is and what it contains.
The display: table; CSS property is not supported in IE. This means that the only way to get the look of a table with CSS is to use a table.
Most browsers display styles on IDs and classes the same way, even if the ID is duplicated on the page. ID is shorter to type, why should I not duplicate it?