Don't apply status bar icons overlay on Oreo, because they can only partially be themed at the moment and therefore some icons disappear when that overlay is applied on O!

self-made icons

This theme will NOT work on a Samsung device

This theme works on Pixel/Nexus devices with Stock Android Oreo. On other devices like Sony it only works partially with Stock Rom. Install at your own risk there
(I wouldn‘t apply status bar icons overlay on Oreo because the icons can only be partially themed and it doesn‘t look that good at the moment)

I strongly advise you to only use this theme on OMS Roms.

Use at your own risk on Stock/Legacy Roms (Except for Stock Oreo)! there can be small/big bugs (Bootloops/not working at all), depending on your Rom/phone!

If you use ProjectFi: DON'T apply status bar icons overlay!

Beta versions in general are not supported.
They are updated to often and it's just impossible to keep up with

xhdpi,xxhdpi,xxxhdpi are officially supported! It should work on lower dpi phones too but there might be some issues!

You can choose between 35 accent colors and 9 background colors

Find a list of themed apps here:
https://drive.google.com/file/d/1wZCWcqDLxWjrAxND21X_0RTzLBypx2Ar/view?usp=sharing

If you have any issues or requests don't hesitate to contact me via email!

follow me on Google+ for more info:
https://plus.google.com/100639474939398785827

Thanks to the themer's chat for a lot of helpful input!!!
Thanks to David Wilson and his Open Source theme , which helped me massively with some overlays!

// Option A //

To download Focus || Substratum Theme (Android Oreo/Nougat) mod from HappyMod.com.
You need enable the option "Unknown Sources".
1. Click on the above link to download Focus || Substratum Theme (Android Oreo/Nougat) mod APK.
2. Save the file in your device Downloads folder.
3. Now tap on Install and wait for the installation to finish.
4. Once it is done, open the game and start playing it right away.

// Option B //

To download Focus || Substratum Theme (Android Oreo/Nougat) from HappyMod APP, you can follow this:
1. Open your browser and download the HappyMod APK file from HappyMod.com - the only official website of HappyMod.
2. Open Android Settings and go into Privacy or Security.
3. Tap the option to Allow Unknown Sources and enable it.
4. Go to your Android downloads and tap the APK file.
5. Follow the directions on the screen to install it.
6. Search Focus || Substratum Theme (Android Oreo/Nougat) in HappyMod App.