JSFiddle - React, Tailwind, and code Playground

HTML

<div id="progress_bar_container">
    <div id="progress_bar_background">
        <div id="progress" style="width: 100px;">
            &nbsp;
        </div>
    </div>
    <div style="text-align: left; display: inline-block;">
        50%
    </div>
</div>

CSS

#progress_bar_container {

width: 240px; /* I increased it, you can remove */
height: 20px;

}

#progress_bar_background {

    display: inline-block;
    background-color: #eaeaea;
    width: 200px;
    height: 20px;
    -moz-border-radius: 15px;
    -webkit-border-radius: 15px;
    -khtml-border-radius: 15px;
    border-radius: 15px;

}

#progress {

    display: inline-block;
    background: #a8c25d;
    height: 20px;
    width: 0px;
    -moz-border-radius: 15px;
    -webkit-border-radius: 15px;
    -khtml-border-radius: 15px;
    border-radius: 15px;

}