Gives a style value a higher weight in the cascade order. Values with higher weight or importance in the order of cascade win out against lower weighted styles when conficts occur.
!important allows users to override or have their own rules be more specific then the authors rules.
You should avoid using !important in as much as possible in your author stylesheets. They make reading and debugging your styles harder.
The order of importance of rules in stylesheets in ascending order.
- User Agent stylesheets. (least specific)
- User stylesheets.