Earlier quoted context omitted.
I dont do this repeating class business but CSS Tricks 'css guidelines' web page says that when you do : '.collection li', it first searches through the page for all 'li's then wittles it down to the ones within the correct parent. Essentially that css selectors work from right to left. So I guess the idea is that classing up the li elements within a parent may be marginally quicker? I have never bothered though. Doe…
Modern browsers do their best to optimize typical use-cases for CSS selectors and .collection li for sure will be handled optimally. You shouldn't worry about CSS selector performance unless you have to provide good performance for very old browsers or hit specific performance problem. Optimize for humans, not for computers.
https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Writi...
They explicitly state using css classes is more performant than using tags.
I'd be interested in a CSSPerf(Do they have those?)