Designing Dark Mode for a Firefox Extension: Beyond Just Inverting Colors Every new tab extension should support dark mode. But good dark mode isn't just filter: invert() or flipping colors — it requires intentional design decisions. Here's how I implemented dark mode in the Weather & Clock Dashboard extension. The Core Principle: Surfaces, Not Just Colors Good dark mode thinks in surfaces: Background : 0% lightness (true black) vs 12-15% (near-black) Surface 1 (cards, panels): slightly lighter than background Surface 2 (hover states): slightly lighter than Surface 1 Text primary : ~87% opacity white Text secondary : ~60% opacity white Material Design's dark theme guide is worth reading: this elevation-based approach prevents dark mode from looking flat.…