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Is this too risky to merge, or something,@cderv?

I'm trying to decide whether I should wait for it or figure out how to pull in this code when building our books.

I want to find time to test it and see the impact it has, especially on current users. As you have tested it, is this something that some users would want to opt-out ?

My understanding was that it was for mobile only, but the current change seems to also modify the CSS for current style of non mobile view. I don't want to force changes of style to all existing bs4_book.

Maybe we need some media query rule to use the CSS based on size of screen ?https://ui.dev/rwd/develop/browser-feature-support/media-queries-for-common-device-breakpoints