JSFiddle - React, Tailwind, and code Playground

HTML

<body style="vertical-align: middle;">

<form>
<div align="center" style="vertical-align: middle;">
<h1>blabla</h1>
<label>
<span>Username: </span><input id="userName" type="text" name="userName" />
</label><br/>

<label>
<span>Password: &nbsp;</span><input id="passWord" type="password" name="passWord" />
</label><br/>
<input type="button" value="Login" />
</label>

</div>
</form>

</body>

CSS

html, body {
    height:100%;
    width:100%;
    margin:0px;
}
body {
    display:table;
    vertical-align:middle;
}
form {
    display:table-cell;
    vertical-align:middle;
    width:240px;
    margin:0px auto;
}