That is not the goal. Read TFA; their example specifically still loads small.css by dynamically creating a <link> element after pageload (in a RequestAnimation

That is not the goal. Read TFA; their example specifically still loads small.css by dynamically creating a <link> element after pageload (in a RequestAnimationFrame or onLoad). The goal is to have the CSS already present when the "above-the-fold" content renders, so that it's that much faster to render correctly, improving user experience.