JSFiddle - React, Tailwind, and code Playground

HTML

<textarea required="required"></textarea>
<br>
<textarea required="required">Type here...</textarea>

CSS

textarea {
    width: 400px;
    -webkit-transition: height .2s ease-in;
    -moz-transition: height .2s ease-in;
    -o-transition: height .2s ease-in;
    transition: height .2s ease-in;
}
textarea:empty, textarea:invalid {
    height: 50px;
}
textarea:focus, textarea:valid {
    height: 200px;
}