JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wr">
    <textarea></textarea>
    <div class="f2"></div>
</div>

CSS

.wr {position:relative;}
.f2 {
    border:1px solid silver;
    width:200px;
    height:100px;
    padding:5px; position:absolute; top:0; z-index:1;
}

textarea {width:190px;height:90px; position:absolute; top:0; z-index:2; margin:8px 0 0 8px;}

textarea:focus ~ .f2 {border:1px solid red;}