[jackie_w]

Originally Posted by hobnail

I vaguely recall banging my head against this a long time ago and never found a solution.

If you want the coloured box to match content width you can add a span with padding/colours. Something like this:

<h1 class="heading"><span class="decor">CHAPTER 1</span></h1>
<h1 class="heading"><span class="decor">Chapter One Hundred and Fifty-Two</span></h1>

.heading {
    font-family: sans-serif;
    font-size: 1.1em;
    margin: 3em 0;
    text-align: center;
    text-indent:0;}

.decor {
    background: teal;
    color: white;
    padding: 0.5em 1em;
}