JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <div class="wrap clearfix">
        <h1>Текст Текст Текст Текст Текст</h1>
        <div class="line"></div>
    </div>
 </body>

CSS

.clearfix {
  *zoom: 1;
}
.clearfix:before,
.clearfix:after {
  display: table;
  content: "";
  line-height: 0;
}
.clearfix:after {
  clear: both;
}

.wrap {
    width: 400px;
    border: 1px solid black;
}
h1 {
    margin: 0;
    padding: 0;
    display: inline;
    float: left;
}
.line {
    float: left;
    background: blue;
    height: 20px;
    width: 100px;
}