[JSWolf]

Originally Posted by DuckieTigger

You are correct. The -100px won't work on a 7" 300DPI Oasis. It likely won't work on your 6" 300DPI PW3 either. I tried and even -55px still works on the 7" without cutting off words. Since the margin appears to be a fixed size relative to the width of the page this workaround should do the trick:

html {
  margin-left: -6.5%;
  margin-right: -6.5%;
  break-inside: avoid !important;
}

I tested with -5% (still big margin), -10% (too much, cuts off text), -8% (goes all the way to the edge in portrait mode, cuts off text in landscape). It appears -6.5% is the biggest offset that leaves a very small margin in portrait mode, and none in landscape mode.

Would be nice if you could test this out on your 6" PW3 and see if it gives the same result of tiny margin in portrait mode, (almost) none in landscape. If that is the case it might work on all 300DPI Kindles, possibly even on lower resolution ones.

I'll be able to try it on a PW3 and a PW5. Just not until about a week.