WordPress Note: Fixing the Judder on a Cover Block in Safari

In addition to making weird footnoted dance theater, I'm a core contributor to the WordPress project and run a web design business, Typecoast. I posted a little solution on the Typecoast blog today for a shaking/jitteriness problem that shows up with something called a Cover Block. Pairing a fixed background with a duotone effect on the Cover Block causes an unsightly juddering effect, and it can be fixed with CSS.