JSFiddle - React, Tailwind, and code Playground

HTML

<div class="events">
    <div class="tt_username"><p>Text!</p></div>
</div>

CSS

.events{
    height:100px;
    position: relative;
}
.tt_username{
    position: absolute;
    top:0px;
    height: 100%;
    width: 30px;
    background: #ccc;
    text-align: center;
}

.tt_username p{
    -webkit-transform: rotate(270deg);	
    -moz-transform: rotate(270deg);
    -ms-transform: rotate(270deg);
    -o-transform: rotate(270deg);
    transform: rotate(270deg);
    background: #ff0000;
    font-size: 16px;
}