Update 23: Dark mode

Lemniscate now has a dark mode. It follows your device setting by default, and a sun or moon button in the header lets you switch for this browser; your choice is remembered only in your own browser. The look keeps the same deep navy, gold and cream, with cream text on navy and a softer gold for small text so it stays readable. Every page and every workspace tab was checked in both modes on a phone-sized screen (all routes) and spot-checked on desktop.