AdminLTE is by far one of the great examples of what Bootstrap CSS can do if it’s properly bundled with pre-defined UI elements used for Admin control panels. Right now, there’s a massive amount of various admin panels on the net.
I’ve made a quick Proof of Concept on how we can easily convert default AdminLTE layout into a dark theme, with a bit of help from grunt and yarn. AdminLTE Midnight Dark Theme is available on GitHub, with detailed description on how to run it in dev mode via AdminLTE repo. You might find it useful to go through customisation instructions first, before diving into contribution phase.
Vendor prefixes for properties, functions, @-rules and even full declarations are automatically generated – based on trustedsources – so you can maintain cross-browser support while keeping your source code clean and easy to maintain.