In JDK-8248566 we started to make javadoc pages more usable on smaller devices. However, the navigation bar still is problematic in this context. It can use up a substantial part of the screen, and the navigation links are broken in unregular ways if they do not fit in a single line.

The common way to solve these problems is to use a collapsible navigation bar for small dispays. This can be achieved via media queries which are already used in current javadoc.