DEPRECATED! Use fix_telegram_fonts.reg to override fonts without patching EXE. In 5.0.0 Telegram Desktop you should set
Chat settings -> Font family optiontoSystem Value.
All telegram fonts can be found in lib_ui and implementaion of font selection is here.
Patch Telegram fonts to Arial / Tahoma. Makes text more clear.
It's slow but working. If you have a time make it faster on C++.