JSFiddle - React, Tailwind, and code Playground

HTML

<form id="form1" runat="server">
    <div class="editor-ribbon"></div>
    <div class="wrapper">
        <div class="container" maxlenght="20" contenteditable="true">

        </div> 
    </div>
  </form>

CSS

.wrapper {
        width:960px;
        height:auto;
        min-height:600px;
        margin-left:auto;
        margin-right:auto;
        border-left:1px solid #cfcfcf;
        border-right:1px solid #cfcfcf;
        box-shadow:0px 10px 10px #6f6f6f;
        background-color:#ffffff;
        margin-top:100px;
    }
    .container {
        width:100%;
        height:auto;
        min-height:800px;
        padding:10px;
        font-family:Arial;
        border:1px solid #3f3f3f;
        box-sizing:border-box;
        -moz-box-sizing:border-box;
        -webkit-box-sizing:border-box;

    }
    .editor-ribbon {
        height:100px;
        position:fixed;
        left:0px;
        top:0px;
        width:100%;
        border-bottom:1px solid #cfcfcf;
        width:100%;
        background-color: gray;
            }