JSFiddle - React, Tailwind, and code Playground

HTML

<div class="main">
    <div class="header"></div>
    <div class="right-bar">
        <div class="chat-user-content"> 
          <span class="chat-user-photo">
            <img src="http://d13yacurqjgara.cloudfront.net/users/25963/avatars/mini/2013-avatar_(1).png" />
          </span>
            <span class="chat-user-name">Fulano Silva</span>
            <span class="chat-user-status online"></span>
        </div>
    </div>
</div>

CSS

html, body {
    margin:0;
    height: 100%
}
.main {
    position: relative;
    background-color:#383f59;
    width:100%;
    height:100%;
}
.header {
    width:100%;
    height:35px;
    background-color:#668bcc;
}
.right-bar {
    width:35%;
    background-color:#f5f8fa;
    float:right;
    height: 100%;
    /* para falta de suporte */
    height: -webkit-calc(100% - 35px);
    /* para Chrome */
    height: -moz-calc(100% - 35px);
    /* para Firefox */
    height: calc(100% - 35px);
    /* para suporte nativo */
}
.chat-user-content {
    height:60px;
    display: table;
    width: 100%;
    background-color:#f5f8fa;
    border-bottom:1px #d8dde6 solid;
}
.chat-user-content:hover {
    background-color:#e1e5eb;
}
.chat-user-content span {
    vertical-align:middle;
    display: table-cell;
}

.chat-user-photo{
    width:25px;
}
.chat-user-photo > img{
    border-radius: 50%;
    padding:10px;
    width:50px;
    height:50px;
}
.chat-user-name{
    font-family:Verdana;
    font-size:18px;
    text-align:left;
    color:#797f8a;
}

.chat-user-status:after {
    border-radius: 50%;
    height:15px;
    width:15px;
    display:block;
    content:"";
}

.online:after {
    background:#a7ba3d;
}