But now if I change the dark theme at runtime and use toggleColorLayerLuminance JavaScript function defined above in the razor event handler the code updates the luminance layer and background color ...

Examples download "bootstrap-5.3.0-examples.zip" is missing file for dark mode "color-modes.js" ... is missing JavaScript file "color-modes.js", ... Would be a nice idea for convenience to include it ...

Two key excerpts from a couple of quick-read web pages loaded with visual examples: “Although changing a background on a Web page to a bright color can add excitement, these backgrounds can also make ...