JSFiddle - React, Tailwind, and code Playground

HTML

<span>The following equation is perhaps the most well known of all: E<sub>a</sub> = mc<sup>2</sup>.  And it gives an opportunity to try out a superscript and even throw in a superfluous subscript!  I'm sure that Einstein would be pleased.</span>.

CSS

sup, sub {
  vertical-align: baseline;
  position: relative;
  top: -0.2em;
}

sub {
  top: 0.2em;
}