Cascading is something that makes CSS even more powerful. Style sheets cascade when The Web Writer or user (or both) have created an order of precedence for the browser to apply the style rules in multiple sheets. The style rule or sheet that has the highest precedence is the one that is used. The following list is a simplification of how your browser decides precedence for a style:
- Look for the style element that is created, if it is not in the document, use the default rules in the browser
- Determine if any of the style rules are marked as important and apply those to the appropriate elements
- Any style rules in the document will have precedence over the default browser settings
- The more specific the style rule, the higher the precedence it will have
- Finally, if two rules apply to the same element, the one that was loaded last will have the highest precedence
