JSFiddle - React, Tailwind, and code Playground

HTML

<div class="comment-container">
    <textarea class="commentA"></textarea>
</div>
<textarea class="commentB"></textarea>

CSS

body {margin:0;padding:0;}
.comment-container {
    padding:10px;
}
.commentA {
    width:100%;
    min-height: 200px;
    -webkit-border-radius:5px; /* Chrome & Safari */
     -khtml-border-radius:5px; /* Konquerer */
       -moz-border-radius;5px; /* Firefox */
        -ms-border-radius:5px; /* IE */
         -o-border-radius:5px; /* Opera */
            border-radius:5px;
    -webkit-box-shadow: 1px 1px 2px #ccc;
     -khtml-box-shadow: 1px 1px 2px #ccc;
       -moz-box-shadow: 1px 1px 2px #ccc;
        -ms-box-shadow: 1px 1px 2px #ccc;
         -o-box-shadow: 1px 1px 2px #ccc;
            box-shadow: 1px 1px 2px #ccc;
}
.commentB {
    margin: 10px;
    display: block;
    overflow: auto;
    border-top-left-radius: 5px 5px;
    border-top-right-radius: 5px 5px;
    border-bottom-right-radius: 5px 5px;
    border-bottom-left-radius: 5px 5px;
    -webkit-box-shadow: rgba(0, 0, 0, .2) 1px 1px 3px;
    -moz-border-radius: 5px;
    -webkit-border-radius: 5px;
    min-height: 200px;
    width: 100% 
}