This repo contais some Solid Dark themes for Telegram Desktop, Android (with X) and MacOS. Don't forget to Subscribe to @SolidDarkTheme channel to get news and updates ;)

Choose platform below or scroll down to installation instructions and screenshots.
Telegram Desktop
Android
MacOS
Telegram X (Android)

Installation:
• Open Releases section and find the most recent release tagged [TDesktop].
• Download file with tdesktop-theme extension and send it to yourself in Telegram.
• Click on uploaded file and press "Apply Theme".

Here's for example how Solid Dark Green for TDesktop looks like:

Also looks fine in JetBrains' IDEs (IDEA, pyCharm and so on...)

There's an official guide how to make themes (and also an unofficial Russian version of the guide)

1. Edit colors.tdesktop-theme file.
2. Change background (if you want). Tiled backgrounds should be named tiled.png or tiled.jpg while normal backgrounds should be names as background.png or background.jpg.
3. Pack both files into zip-archive and rename it as YOUR-THEME.tdesktop-theme (watch the extension!).
4. Send it to any chat in Telegram Desktop, then download, click and apply!
5. If you want to revert to default theme, click Use default color theme button in settings.

Installation:
• Open Releases section and find the most recent release tagged [Android].
• Download file with attheme extension and send it to yourself in Telegram.
• Click on uploaded file and press "Apply Theme".

Screenshot:

Installation:
• Open Releases section and find the most recent release tagged [macOS].
• Download file with palette extension and send it to yourself in Telegram.
• Click on uploaded file and press "Apply Theme".

Screenshot:

Installation:
• Open section and find the most recent release tagged [android_x].
• Download file with tgx-theme extension and send it to yourself in Telegram.
• Click on uploaded file and press "Apply Theme".

Screenshot: