JSFiddle - React, Tailwind, and code Playground

HTML

<div id="bar">
    <div id="index">1</div>
    <div id="vertical_text">Vertical Text</div>  
</div>

CSS

#bar{
    height:400px;
    width:50px;
    background-color:#ccc;
}

#index {
    font-size: 30px;
    font-weight: bold;
}

#vertical_text{
    width:130px;
    height:50px;
    -ms-transform:rotate(270deg); /* IE 9 */
    -moz-transform:rotate(270deg); /* Firefox */
    -webkit-transform:rotate(270deg); /* Safari and Chrome */
    -o-transform:rotate(270deg); /* Opera */
}