go it Library > Color and click on “+” - this lets you create a color with a Dark & Light value.
Bind whatever you want to the Library color (you will see the “From Library” button at the bottom of the color picker).
To switch between light and dark mode - just add a button or toggle - add a workflow “on change” > “change theme” - and then bind to formula switch ( browser.theme, “dark”,“light”,“light”,“dark”) - and that’s it.
Yes … you need to bind ANY and ALL elements that you want to have different colors in light vs dark themes. Including text. Basically - you can think of “library colors” as colors that have two modes.