You will be required to install the Substratum Theme Engine and have root access OR the Andromeda add-on, if you want to apply this theme:
For rootless theming with Substratum, you will have to purchase the Andromeda add-on pack:
A bare-bones Black theme for Android Oreo that focuses on nothing more than theming the system. The theme is best used with STOCK or AOSP based ROMs. It will definitely work on any Android Oreo system, but it will not theme it as perfectly as on vanilla Oreo. For other apps, I recommend using my Fresh Theme (https://play.google.com/store/apps/details?id=baka.sai.theme) which is also available for free!
If you see un-themed/partially themed notifications even after installing the theme, please manually reboot the device (recommended) OR clear all your notifications.
System components themed as of now:
• Android system (also themes the Settings app)
• Files (com.android.documentsui)
• Package installer (com.google.android.packageinstaller)
• Settings (com.android.settings)
• System UI (com.android.systemui)
• maybe more...
Known Issues (as of 2018/01/10):
• [No fixes possible for now] WhatsApp, Uber black/dark notification header texts when using dark notification options
This theme is 100% open-source
Contact for support, suggestions, and whatnot:
• Github Issues!
• Substratum Telegram: t.me/Substratum
• Telegram PM: t.me/BakaBakaBaka
• Telegram Group: t.me/SaiThemes