When you log out, there is no cookie that tells AWF what theme you chose, so it just reverts to the default. I have reset the default back to the lighter theme now, but anyone can manually switch to dark theme should they wish.
The Shades of Grey theme displays the posts much wider. This causes longer lines, which are harder to read.
The XF2.1 Default Dark theme is slightly better in that regard but does not loot as appealing visually as Shades of Grey.
Yes, i did not like the visual look of the XF2.1 Default Dark theme. I will remove it. You are right about longer lines being harder to read. Remember how long the lines were on the old forum? Full width!
By all means, add more themes if you wish, but please keep the original light theme as the default.
As I said in the other thread, whilst dark theme is very fashionable these days, I think that makes the content harder to read and causes more eye strain