rulespecificity

Rule specificity refers to the concept of how specific a given rule is within a system, especially in contexts like cascading style sheets (CSS) or programming languages. A more specific rule will take precedence over a less specific rule when both apply to the same element or condition. This prioritization is crucial for predictable behavior and for resolving conflicts.

In CSS, specificity is calculated based on the selectors used. Inline styles have the highest specificity, followed by IDs, classes, and then element selectors. The more selectors that match an element, the more specific the rule. For example, a rule targeting an ID like #myElement is more specific than a rule targeting a class like .myClass, which in turn is more specific than a rule targeting an element like p.

Understanding rule specificity is essential for web developers to ensure their styles are applied as intended. When styles don't appear to work, it is often because a more specific rule is overriding them. Debugging specificity involves examining the selectors of competing rules and understanding their calculated values.

In other programming contexts, specificity can relate to how particular a condition or a pattern is. For instance, in conditional statements, a more narrowly defined condition might be evaluated before a broader one. This principle ensures that the most precise instruction or selection is executed.