[Mz]

Although I am old and have terrible eyesight, I don't have an issue reading HN on mobile. But there are plenty of themes and apps out there that you should try. For exampke:

http://m3mohsen.github.io/HackerNews-DarkTheme/

https://userstyles.org/styles/133209/hacker-news-dark

https://jamesfriend.com.au/hacker-news-theme

http://ihackernews.com/

https://www.bing.com/search?q=hacker+news+android+themes&go=...

And Google search turns up multiple Hacker News apps, though I am not clear how to link that here.