[RbnJrg]

By the way, the OP could try using not only "vh" but also "svh" or "dvh" (for example, Sigil and its plugins, Thorium, Calibre Viewer, accept those units). Regarding units viewport there are much more than vh and wh:

https://www.terluinwebdesign.nl/en/b...h-svw-lvw-dvw/

https://caniuse.com/?search=svh

These new sv* units are especially useful for Android and iOS e-readers. One could try a style with:

.myHeight {
   height: 100vh;
}

@supports (height: 100svh) {
   .myHeight {
      height: 100svh;
   }
}