[bookman156]

That is a mistake. You do not want to alter the margins all around the screen. You really don't. You want to let the person reading set the margins if the program has that as an option. For example, Kobo Readers have the option to change the margins. You don't want to take away the user's choice of margins.

You misunderstand, although I'm not quite sure how, probably reading too quickly. That's what I was talking about. I'm talking about people altering the page margin in their own ereader and how that affects your own use of a margin on say an epigraph page, which as padding is unaffected.

As for line-height, get rid of it it. Kobo has a setting for Line spacing and if you set it, you'll once again ruin the user's choice.

I haven't seen any ereader where setting line-height prevents the reader altering it. Some ereaders ignore what I set anyway, others are benefited because you give access to a line-height that isn't available on the ereader itself.

Do not use px or pt.

Do you not use px for a hr rule? I wouldn't use px for anything else in an epub, and pt never, I was simply saying that I have seen it used.

Leave L/R margins at 0 and no added line height.

Setting a 0.5em margin on the body does no harm, mostly overridden anyway by the device. Setting to 0 is also 'playing around with margins'. I have pointed out a good reason to use line-height.

As for @page, get rid of it. It's not needed.

I don't use that. That's an InDesign export thing. But margin on body is fine.

Your 1.5em top/bottom margins are too large. That would make it slightly more then 3em. Too large for a section break.

Don't agree at all. It's just right. It depends on the book, you shouldn't be so dogmatic about aesthetics. Maybe your aesthetic sense is different to mine. If you want to argue which is better, that's a matter for a boxing ring.

Also, you should be making that line 2px as 1px can be a bit too thin on a 300dpi eInk screen. Also, darksalmon is a bad idea for eInk screens. Leave the line at the default color of black.

Possibly. But I want a line that isn't over-visible. I frankly don't mind if it isn't very visible at all. It's mainly to hold the space for blind people in screen-readers. Sighted people are seeing the space more than the rule. I could even make it invisible, as recommended by the accessibility experts, but I'm less keen on that. It's a space that is respected, and if you see there is a thin grey faint rule there on your eink screen then good. But you may be reading it on an Android reader and be able to see it in colour. And then 2px is certainly too thick. Swings and roundabouts.