Less gaps in css

[EmileTrotignon]

Reduces gaps in css.

Answers issue #1111.

[EmileTrotignon]

Here is a screenshot of an example page :

[panglesd]

We don't really need less gaps in CSS, we need to remove the gap introduced in #999 by the introduction of the grid system, which disabled margin collapse:

the margins of adjacent grid items do not collapse

(From https://www.w3.org/TR/css-grid-1/#item-margins)

The solution you propose changes many margins/paddings (making the result slightly not spaced enough in my opinion, but that's maybe just habits of the previous style) while not solving the original problem! Edit: it does solve it by always having the top margin equal to zero... I don't think that having all elements have a 0 value for margin-top is a valid assumption to make!

We can solve the problem either by going away from the grid system, or modifying the html layout: grouping odoc-preamble and odoc-content in a single element.
I would prefer the second option. It would not affect ocaml.org since they are using the --as-json option which would be unaffected by this change. However, we should be careful to check if the layout change affects odig stylesheet.

[panglesd]

This is not valid css and likely a leftover?

Suggested change

row-gap: ex;

[EmileTrotignon]

Oh ok, I did not know about margin collapse, I just git blame on the line that set the topmost margin and found it was quite old, so I thought this was not introduced recently.

I am a bit anxious about changing the order of elements, but I certainly do not want to drop grid.
Another way to do would be to have a rule like :

.odoc-content:first-child {
  margin-top:0 !important;
}

[EmileTrotignon]

I am also not i agree that assuming every element not to have a top-margin is a bad idea, it seems quite reasonable to me, its a convention that works well, and if a margin-top slips in its a very easy patch to remove it.

[panglesd]

I does not seem acceptable to me to remove all top margins. This would mean that the space between two element would only depend on the top one. That is quite awful!

I opened #1146 with my alternative suggestion.