This is a Demonstration

No images have been used to achieve the rounded corners.
This is some text with a background and transparent borders.
The colors are automatically detected, the work for the web designer is minimal.
It is now even possible to
automatically and correctly apply rounded corners to absolutely sized elements, like this one.
Just another one to demonstrate that all elements with the same class are formatted by the same CornerZap declaration.

How about differently shaped corners? All corners have a different radius, while the top right is not rounded at all. Besides, the corners are anti-aliased; you may need a screen magnifier to properly admire that.