The index page of this blog contains a list of posts. Each item looks like this:
An Invisible Space
There is a one-em gap between the date and the title, which becomes a space when the line is copied. However, when you select the line, no space is highlighted. This is done through the following HTML:
<time>2026-01-08</time><span style="display:inline-block;width:1em"> </span><a href="space.html">An Invisible Space</a>
I really don't know why this behaves the way it does, but I do find it quite neat.