JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <input id="verticalButton" type="submit" Value="Ok"></input>
</div>

CSS

div#container
{
    height: 200px; 
    border: solid 2px green; text-align:center;
    line-height:200px;
}

input#verticalButton
{
     vertical-align: middle
}