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HTML/CSSIntermediate#css#forms
HTML/CSSBeginner#css#selectors#performance
What is the universal selector (*) and what are its performance implications?
The * selector matches every element on the page. It's convenient for resets (box-sizing) but can be slower than targeted selectors on very large DOM trees since the browser must evaluate it against every node; use judiciously, mainly for resets.
Example
*, *::before, *::after {
box-sizing: border-box;
}