This workflow is designed to be used with its native-looking themes collection.
It allows you to select your Alfred's theme accent color and switch between Dark & Light modes. Here are the main commands :
theme install : downloads the 16 native-looking Alfred themes (8 macOS accent colors, in Dark & Light variants)
theme : toggles between Dark & Light Themes on both macOS and Alfred.
theme purple : toggles between the accent color of your choice variant of this set of themes (replace color with either Blue, Purple, Pink, Red, Orange, Yellow, Green, Gray).
Needs at least macOS Mojave, which introduced Dark Mode.