JSFiddle - React, Tailwind, and code Playground

HTML

<h1 class="capitalize">hello world</h1>
<h1 class="capitalize">HELLO WORLD</h1>
<h1 class="capitalize before">world</h1>
<h1 class="capitalize after">hel444lo</h1>

CSS

.capitalize {
  text-transform: capitalize
}
.before:before {
  content: 'hello'
}
.after:after {
  content: 'wor3ld'
}