I just pushed out an update to Linux Sea (an online resource to introduce you to Linux, using Gentoo Linux as an example), including its PDF and ePub versions. The changes are pretty small (see its ChangeLog).
Together with the update, it now also includes a <meta name="viewport"...> so that the document renders better on a mobile device. Not perfect, but at least it’s not small text anymore where you need to pinch-zoom and then scroll left/right all over the place. Same with my blog btw.