Something you very much want to avoid in web design is unreadable text. That can happen when the background color of an element is too close or exactly the color of the text. For instance:
Which could lead to text that’s there, but invisible.
This is … very bad.
You’d never do that on purpose of course! The trouble is it can sneak up on you. For one thing, the default background-color…
CSS Basics: Using Fallback Colors is a post from CSS-Tricks