.big {display:block; margin-top:0.5em; margin-bottom:0.5em;}
    ...
  <div style="max-width:36em">
    This is within the DIV, so it is blue.
    <p>This is within the P, so it is red.<br>
      Another line.<br>
      Another line.<br>
      <span class=big>This text is wrapped in span class big</span>
      Another line (after closing the span).<br>
      Another line.<br>
      This is followed by span class big (and no BR)<span class=big></span>
      Another line.<br>
      Another line.<br>
      This is followed by BR then span class big<br><span class=big></span>
      Another line.<br>
      Another line.<br>
      This is followed by span class big then BR<span class=big></span><br>
      Another line.<br>
      Another line.<br>
      This is followed by BR wrapped in span class big<span class=big><br></span>
      Another line.<br>
      Another line.<br>
    </p>
    This is within the DIV, so it should be blue.
  </div>