If I were to adjust the font size responsively in Tailwind, here's how it would look:
<div className="text-xl sm:text-4xl">Hello World</div>
When working with Material UI, Typography is used for setting text sizes responsively. For example, using h3 on screen sizes "sm" and above can be done like this:
<Typography variant="h1" component="h1">
Hello World
</Typography>