No, not really, and given the length of time ereaders stick around, you’re really probably best off assuming the worst. If there’s something complex layout-wise that I want to do then I often use @supports blocks. For example, in a recent book I worked on I had a layout that would be be accomplished with flexbox, but I started with floats instead and overrode that for better ereaders: https://github.com/standardebooks/harry-harrison_planet-of-t...