MetaFilter embiggen favorite plus minus sign

Makes the + and − signs to add and remove favorites on MetaFilter.com larger for easier access on mobile.

// ==UserScript==
// @name          MetaFilter embiggen favorite plus minus sign
// @namespace     http://userstyles.org
// @description	  Makes the + and − signs to add and remove favorites on MetaFilter.com larger for easier access on mobile.
// @author        Tehhund
// @match         *://*.metafilter.com/*
// @version       4
// ==/UserScript==

function embiggenAllPlusMinus() { // Hit every plus or minus on initial load.
	let allPlusMinusSpans = document.querySelectorAll("a:link[id^='plusminus'");
	for (let span of allPlusMinusSpans) {
		embiggenOne(span);
	}
}

function embiggenOne(tag) {
  let compStyles = window.getComputedStyle(tag);
  let compFontSize = parseFloat(compStyles.getPropertyValue('font-size'));
  if (compFontSize < 25) tag.style.fontSize = '250%';
}

function handleMutationsList(mutationsList, observer) { // Handle mutation events, since adding or removing a favorite removes the old span and creates a new one.
	 for (let mutation of mutationsList) { // Loop over all mutations for this event.
		 let allLinksInMutatedNode = Array.from(mutation.target.querySelectorAll("a:link[id^='plusminus'")); // Get all anchor elements aka links in the mutated node.
		 for (let currentNode of allLinksInMutatedNode) { embiggenOne(currentNode) }; // Call embiggenOne on every link element in the mutated node.
	 }
}

// run once when the page is loaded.
embiggenAllPlusMinus();

// After the first embiggening, observe the main content div for changes such as new comments or adding a Favorite, and run embiggenOne() on the changed tag.
const mutationObserver = new MutationObserver(handleMutationsList);
mutationObserver.observe(document.getElementById('posts'), { attributes: true, childList: true, subtree: true })