Web page I've been working on when the system is set to the Breeze Dark theme. This time with a dark roast plan that includes turnaround (when using something like this I generally prefer to ignore that and have it come up from room temperature instead). The top bar shows and hides the various options and controls to make it easier to see what you're doing when you mess with those instead of drowning in a sea of all the controls including ones you're not using at that moment.
The text in that top menu bar thing is the generic system-ui set bold, so that'll also look different on different platforms while the colors used are Canvas, CanvasText, Highlight, and HighlightText. Graph line colors can be set with color pickers in the Graph options to be whatever the user wants.
Anyway, there's still a decent amount of work that I want to do on this, but I think it's coming together nicely.