Hi all again . . .
I (finally) managed to upload a work-in-progress light theme. (no .zip files or .tar files ? rly?)
It uses the 'classic' set of icons plus a heavily tweaked .css style file.
I expect there's quite a few errors in it - but it might not be a bad place to start if you find the 'default' theme tricky to use. I work in a light office and can't see a thing with the default option.

The uploaded file is here : called BTW

https://lmms.io/lsp/?action=show&file=17231

You'll need to unzip it first.

If you haven't used alternative themes before, it goes in the lmms/data/themes folder along with 'default' and 'classic' .
Then you need to change which theme loads by launching LMMS, and then going to the edit/settings/folders/themes option and changing from 'default' to 'BTW' - you can always reset back to the default theme at any time.