HelloSign: Everything IT requires and Developers love
Let's take a basic on-page link:
<a href="#section-two">Section Two</a>
When clicked, the browser will scroll itself to the element with that ID: <section id="section-two"></section>. A browser feature as old as browsers themselves, just about.
But as soon as position: fixed; came into play, it became a bit of an issue. The browser will still jump to bring the newly targeted element into view, but that element may be obscured by a fixed position element, which is pretty bad UX.
I called this "headbutting the browswer window" nearly 10 years ago, and went over some possible solutions. Nicolas Gallager documented five different techniques. I'm even using a fixed position header here in v17 of CSS-Tricks, and I don't particularly love any of those techniques. I sort of punted on it and added top padding to all my <h3> elements, which is big enough for the header to fit there.