Improve UI

[warreth]

• Neaten the settings page (better organisation)

• Improve dark mode:

  • make bottom bar more different from the rest of the app
  • Apply Dark mode in the reader itself
  • Dont make the enabled button black when in darkmode (same with light mode)
  • Make bottom bar black when in light mode

• Cant scroll nor tap epubs, they just always go back to the first page