JSFiddle - React, Tailwind, and code Playground

HTML

<h1>Hotgeart il est trop coooool</h1>
<h2>Comments :</h2>
<div class="comments-list">
    <div class="comment" id="comment_1"> <a href="#">Hotgeart</a> : Coucou c'est moi zqd qzd qzd qzd qzd zqd qzd qzd
        <br>liloulol <span class="reply">Reply</span>

        <form id="reply-comment">
            <textarea placeholder="Ton commentaire"></textarea>
        </form>
    </div>
    <div class="comment" id="comment_1"> <a href="#">Hotgeart</a> : J'aime les poneyssssssss §§§§§! <span class="reply">Reply</span>

        <form id="reply-comment">
            <textarea placeholder="Ton commentaire"></textarea>
        </form>
    </div>
    <div class="comment" id="comment_1"> <a href="#">Hotgeart</a> : Coucou c'est moi qzdgtrhrh rthrth rthrt rh rth rthrth rt <span class="reply">Reply</span>

        <form id="reply-comment">
            <textarea placeholder="Ton commentaire"></textarea>
        </form>
    </div>
</div>

CSS

body {
    background: #333;
    font-family: sans-serif;
    font-size: 12px;
}
a, .reply, h1 {
    color: grey;
    text-decoration: none;
    cursor: pointer;
}
.reply {
    font-size: 11px;
    float: right;
    display: block;
}
.comments-list {
    background: #f7f7f7;
    border: 1px solid #eee;
    padding: 10px;
    border-radius: 5px;
}
.comment {
    background: #fefefe;
    padding: 5px;
    border-radius: 4px;
    margin-bottom: 10px;
}
textarea {
    width: 100%;
}
#reply-comment {
    display: none;
}

JavaScript

$(".reply").click(function () {
    if ($(this).next("#reply-comment").is(":visible")) {
         $(this).next("#reply-comment").slideUp();
    } else {
        $(this).next("#reply-comment").slideDown();
    }
});