JSFiddle - React, Tailwind, and code Playground

HTML

<body>
  <form>
    <p>First Form</p>
  </form>
  <form>
    <p>Second Form</p>
  </form>
</body>

CSS

form:first-child {
  border: 1px solid blue;
}
form:last-child {
  border: 1px solid red;
}