What a hero section is
The hero section is the block at the top of a page that a visitor sees before scrolling: a headline that says what this is, a line of supporting text, one or two calls to action, and a backdrop. The name comes from print, where the hero image was the big picture on the opening spread. On the web it is the same job — carry the claim, and give the eye somewhere to land.
What goes behind the headline
Three things usually: a photograph, a video, or something drawn. A photograph is cheap and static. A hero background video costs megabytes, loops where everyone can see the seam, and softens the moment the screen is sharper than the file. A shader is a formula and a few numbers: every frame is computed at the resolution of the element it fills, so there is no loop to spot and nothing to blur.
Keeping the text readable
A hero animation that fights the headline has failed at the one job it had. Every shader here carries a vignette and a vibrancy control, so the middle can be pulled down until the type sits clear of it — the demo above is running a vignette at 0.65 for that reason. The renderer also holds a still frame for readers who ask for reduced motion, and stops drawing entirely once the hero scrolls out of view.
