I made a new KOReader plugin called Reading Style that makes book layout customization much easier.
It gives you simple controls for things like paragraph indentation, spacing, line spacing, margins, headings, images, colors, and more — without digging through Style Tweaks or writing CSS.
It also supports presets, per-book/language settings, and a Quick Style screen.
Reflowable formats only (EPUB, etc.).
Repo:
https://github.com/omer-faruq/readingstyle.koplugin
Menu: Style → [Reading style], next to Style tweaks
The plugin was developed with Claude, with me directing the development and testing it on my device. Feedback and bug reports are welcome!