I know I am late to comment here but no one has shared another workaround so I thought I would share mine! I have started using a browser extension on Microsoft Edge called Dark Reader - Microsoft Edge Addons which does a pretty decent job at turning any webpage, including community and management portal, to dark mode. It isn't always perfect, sometimes images don't work with a dark background or code blocks don't change colour, but is very easy to turn on and off when its needed.

It looks like the same extension is available for Chrome too, although I haven't tested it. I'll still advocate for real options in the management portal but this workaround works quite well for me! 

I believe concatenation runs the risk of SQL injection - a good example is given in the article Optimizing SQL LIKE Security, Performance and Best Practices | InterSystems. The example in the article shows someone add an `OR 1=1` parameter to be added to a WHERE clause to access all available data, rather than just the data they should access. As I understand it, preparing the statement with ? for parameters prevents this risk.