Make scrollbar placement more natural when using sidebar

[MangelMaxime]

Hello,
This is a proposition.

When using sidebar, a margin-top is automatically applied to the "main content" of the page.

This cause the scrollbar to be placed in a not natural position:

I think that this extra margin-top should be removed so the scrollbar is placed naturally at the top of the page.

missing/src/components.css

Lines 91 to 95 in 97451ea

	& > :nth-child(2) {
	overflow: auto;
	--full-width: calc(100vw - 25ch);
	margin-top: var(--gap);
	}

In general, there will naturally be a spacing at the top of the page because it should in general start with a heading element or a main to center the content on the page. And if not, user can add the spacing if needed.