<!DOCTYPE html>
<!--
 | Whitespace preceding a <br> element should be collapsed.
 |   https://www.w3.org/TR/css3-text/#white-space-phase-1
 -->
<html>
<head>
  <style>
    body {
      margin: 0px;
      font-family: Roboto;
      font-size: 50px;
      font-weight: bold;
    }
    .wrap-block {
      width: 180px;
    }
    .blue-background {
      background-color: #4285f4;
    }
    .collapsed {
      background-color: #f50057;
    }
  </style>
</head>
<body>
  <div class="wrap-block blue-background">Hi there <br>world!</div>
  <div><span class="blue-background">Hello, <br></span>world!</div>
  <div>Hello,<span class="collapsed"> <br></span>world!</div>
  <div>Hello,<span class="collapsed"> </span><br>world!</div>
</body>
</html>