[FEATURE] Provide an help to eyes with dark-theme mode version

[pasqualedante]

It would be great to have a dark version of purplemine2. It would be perfect if this version was enabled by default based on the light \ dark theme set in the operating system.

Thanks in advance.

[mrliptontea]

Hi,

This would be a great addition, however, it's not a small thing to build. As I don't use Redmine anymore I won't be picking up this work but I would welcome a Pull Request.

[alexhell]

beside changing/adjusting the colours, what does @pasqualedante and @mrliptontea would like to see.
I would like to have a dark version too. I would like to hire a designer. But till now, I would just let him adjust a _custom-variables.scss. This wouldn't allow you to switch between dark and light mode in redmine itself. In such a case, a standalone theme like DarkMine would even be better, as you could switch it in Settings.

What do you think?

[pasqualedante]

@alexhell for me, your proposal might be an acceptable compromise.