Going through the lists of easy things to make the site more usable, I came across Simon’s post about using LLMs to add dark mode to his site. Using the literal exact same prompt with Opus 4.6, over my morning cup of coffee, Claude added dark mode. I sat at the counter with one of my kids and tested it out. Worked perfectly.
Now the site will follow your OS-level dark mode setting, or if you override it by clicking the little icon in the footer, it will remember your choice. Easy.