yarkov.tech/public/assets/js/load-code-highlight.js

/**
 * This script will load the properly code highlithing theme based on user theme
 * It is important to insert it after detecting a user theme
 * and assigning the `window.theme` property
 */

if (window.theme) {
	/* the {theme} in the path will be dynamically changed */
	const PATH = `/assets/css/code-highlight-{theme}.min.css`;
	const $head = document.getElementsByTagName("head")[0];
	const getPath = (theme) => PATH.replace(`{theme}`, theme);
	const createLink = (theme, media) => {
		const $link = document.createElement("link");
		$link.rel = "stylesheet";
		$link.type = "text/css";
		$link.href = getPath(theme);
		$link.media = media;
		return $link;
	};

	/* init links to load them first */
	const $light = createLink("light", "none");
	const $dark = createLink("dark", "none");

	const toggleMedia = (theme) => {
		switch (theme) {
			case "light":
				$light.media = "all";
				$dark.media = "none";
				break;
			case "dark":
				$light.media = "none";
				$dark.media = "all";
				break;
			default:
				break;
		}
	};

	toggleMedia(window.theme);
	$head.appendChild($light);
	$head.appendChild($dark);

	window.addEventListener("onthemetoggled", ({ detail: newTheme }) => toggleMedia(newTheme));
	window
		.matchMedia("(prefers-color-scheme: dark)")
		.addEventListener("change", ({ matches: isDark }) => {
			return isDark ? toggleMedia("dark") : toggleMedia("light");
		});
}