This lua script is ported from javascript version of https://github.com/zxhzxhz/mpv-chapters And some style is taken from https://github.com/oltodosel/mpv-scripts#show_chapterslua
To use, just add to scripts forlder.
You can turn off the style by setting this "use_u_style" variable to false. And then you can change the variables in option table.
TODO: Handle with large number of chapters