TAG tried that with the interstitial appendix chapters.
Older kindles and the b&w kindles are extremely averse to diffrent fonts, and definitely color.
Things come out very unreadable. He got lots of complaints and did a lot of reformatting, and it’s still not great for some people.
It’s very frustrating, but if you want a nice looking book, the Apple Store is the place to go. If the author owns a Mac (since the only way to go there directly is via a Mac–no PC; you can get there indirectly via Smashwords etc, but then you have basically remove all formatting)
“Written for iBookstore” books can go crazy on fonts, colors, typestyles and color pictures. They are very graphical. But this is because you can only read them on iphones, ipads and computers. All of which are high resolution and color.