Some Awesomeness from the Folks at the W3C
Dynamic outlines: the 'outline' property
The 'outline-color' accepts all colors, as well as the keyword 'invert'.'Invert' is expected to perform a color inversion on the pixels on the screen.This is a common trick to ensure the focus border is visible, regardless of color background.
- Outlines do not take up space.
- Outlines may be non-rectangular.
Outlines have been around since CSS2.1, but hadn't heard about them.