How to switch between Light and Dark theme in Spark for Mac

Spark for Mac by Ukrainian developer Readdle is one of the best email apps for iOS and macOS. On Mac, Spark supports Mojave's Dark Mode. But what if you'd like to use Spark's darkened interface even if your Mac is set to use the default Light appearance (aka Aqua)? Spark lets you do that as well, and we show you how in this step-by-step tutorial.