This script will find all CSS statements and sort them by the impact that have on the current DOM

index.js

// Finds the most impactful CSS statements based on DOM impact
const allRules = Array.from(document.styleSheets).map(s => Array.from(s.rules).filter(e => e.selectorText)).flat()

const removePseudo = selector => selector.split(',').map(s => s.replace(/::[^ ,]*/g, '').trim()).filter(Boolean).join(', ')

const results = allRules.map(r => {
   // removes the pseudo elements and pseudo classes
   const impactedNodes = document.querySelectorAll(removePseudo(r.selectorText)).length;
   return {
      impactedNodes,
      selectorText: r.selectorText,
      selectorText: r.selectorText,
      cssText: r.style.cssText,
   }
}).sort((a,b) => b.impactedNodes - a.impactedNodes)

console.log(results)