Oh woes, my mid-2011 MacBook Air no longer has enough narwhals under the hood to run MacOS Mojave. No dark mode for you, my geriatric little laptop. I am sort of worried that activating dark mode merely opens a portal to Hell for Finestre, the Demon of Such Things, to wander through. She's lovely, of course, but like most demons, kind of evil. She did, after all, put Steve Jobs on Hell's Microsoft Help desk. For eternity. Then he gets moved to IBM Outsourced Solutions. You should hear him wail, even by Hell's standards of constant pitiful wailing, it's something special. They use it as elevator muzak.
ETA: I put it on my iMac. It seems to have broken precisely nothing. Adobe CC and Affinity work, even the ancient Office 2011. Finestre popped around for a cup of tea the moment I entered the Dark Mode. Inspiring eternal torment is thirsty work, or so she says. And can I get her a new iPhone? It's all Nokia in Hell.
EETA: No worries though, they're moving to Blackberry soon.