Comment by nolanl

Author here. I actually did some research on CSS selector performance: https://nolanlawson.com/2023/01/17/my-talk-on-css-runtime-pe...

The TL;DW is: yes, class selectors are slightly more performant than attribute selectors, mostly because only the attribute _names_ are indexed, not the values. But 99% of the time, it's not a big enough deal to justify the premature optimization. I'd recommend measuring your selector performance first: https://developer.chrome.com/docs/devtools/performance/selec...