How Does CSS Selector Precedence Work in Determining Style Application?

Understanding Selector Precedence in CSS

When multiple CSS selectors target the same element, a specific order of precedence determines which one wins. This is particularly important when modifying legacy applications where CSS rules may become entangled.

Selector Specificity

Selectors vary in specificity, and the more specific selector generally takes precedence. Here's the hierarchy:

• Inline style rules (e.g.,

  )

• !important rules (add !important to a rule to override all others)
• ID selectors (#id)
• Class selectors (.class)
• Element selectors (tagname)

Specificity Tiebreakers

In cases where selectors have equal specificity, the following tiebreakers are used:

1. Last Declaration: The rule declared last in the CSS file will take precedence.

Exceptions to the Rule

While it's generally recommended to avoid duplicate rules for the same property, it's not uncommon to specify broad brush rules followed by more specific rules for specific cases. This is entirely acceptable, and the precedence rules still apply to ensure the desired rendering.

Conclusion

Understanding selector precedence in CSS is crucial for managing legacy code and ensuring the correct application of styles. By adhering to the established hierarchy and tiebreaks, developers can confidently modify code without disrupting the desired visual appearance.

The above is the detailed content of How Does CSS Selector Precedence Work in Determining Style Application?. For more information, please follow other related articles on the PHP Chinese website!