What does !important mean in CSS?

Question

What does !important mean in CSS?

Is it available in CSS 2? CSS 3?

Where is it supported? All modern browsers?

Answer 1

It is used to influence sorting in the CSS cascade when sorting by origin is done. It has nothing to do with specificity like stated here in other answers.

Here is the priority from lowest to highest:

1. browser styles
2. user style sheet declarations (without !important)
3. author style sheet declarations (without !important)
4. !important author style sheets
5. !important user style sheets

After that specificity takes place for the rules still having a finger in the pie.

References:

• http://www.w3.org/TR/CSS2/cascade.html#cascade
• https://russmaxdesign.github.io/maxdesign-slides/02-css/207-css-cascade.html