I modified Anonymous san's yeah highlighter script to make it more gradual

It's my first time programming in javascript, so please tell me if there's anything st00pid ヽ(´ー｀)ノ

// ==UserScript==


// @name         Heyuri Yeah Highlighter (better)


// @namespace    heyuri-yeah-highlight-better


// @version      1.0


// @description  Highlights reply posts based on Yeah count (like a Futaba★Channel userscript)


// @author       Heyuri Applicable Research & Development


// @match        https://img.heyuri.net/*


// @grant        none


// ==/UserScript==



(function () {
	"use strict";

    const red_initial = 235;
    const green_initial = 224;
    const blue_initial = 210;

    const red_reach = 0;
    const green_reach = 239;
    const blue_reach = 55;
    const reach = 15; //how many "Yeah" needed to make the post go from color initial to color reach


	function applyHighlighting() {
		document.querySelectorAll(".post.reply").forEach(post => {
			post.removeAttribute("style");

			const sod = post.querySelector(".sod");
			if (!sod) return;

			const match = sod.textContent.match(/\d+/);
			if (!match) return;

			const count = parseInt(match[0], 10);

            const red = Math.round(red_initial - (((red_initial - red_reach) / reach) * count));
            const green = Math.round(green_initial - (((green_initial - green_reach) / reach) * count));
            const blue = Math.round(blue_initial - (((blue_initial - blue_reach) / reach) * count));
			const color = "rgb(" + red + ", " + green + ", " + blue + ")";

			post.style.backgroundColor = color;
		});
	}

	const observer = new MutationObserver(() => {
		applyHighlighting();
	});

	observer.observe(document.body, {
		childList: true,
		subtree: true,
		characterData: true
	});

	applyHighlighting();

})();