[JSWolf]

Originally Posted by Turtle91

Every time you say something like this it proves you don’t pay attention to anyone’s posts.

Your statement is not true.

You simply need to use fallback coding.

CSS:
img {
  width:90%;
  width:90vw;
}

If your device app supports vw it will use it. If it doesn’t support it, it ignores it (as required by ePub spec) and “falls back” to the previous coding:90%

This is how CSS works, Jon. Please stop intentionally telling people things you know are incorrect.

Your fallback code does not work with the older RMSDK. The second width: is what's used and because ADE doesn't do vw, the wide: is ignored. Do you have a fallback that works? Given that % works, why use vw?