JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html>
    <head>
        <title>Q&A</title>
        <meta http-equiv="content-type" content="text/html; charset=utf-8">
    </head>
    
    <body>
        <div id="content">
            <div class="about_header">
                <div class="about_header_text">Q&A</div>
            </div>
            <div id="backtolisting">Back To Listing</div>
            <div id="topichead">
                <div id="topicheadblock"></div>
            </div>
        </div>
    </body>
</html>

CSS

/* ЦЕНТРАЛЬНАЯ ЧАСТЬ - НАЧАЛО */

.about_header {
    width: 540px;
    height: 33px;
    background-color: #616381;

}

.about_header_text {
    font-size: 18px;
    color: #ffffff;
    float: left;
    text-transform: uppercase;
    padding: 9px 10px 7px 10px;
}


#backtolisting {
    margin: 0;
    padding: 0;
    text-align: left;
    clear: left;
}


/* ЦЕНТРАЛЬНАЯ ЧАСТЬ - КОНЕЦ */