[m-rev.] for review: update backends page on website

[Julien Fischer]

On Wed, 19 Jan 2022, Zoltan Somogyi wrote:

> I have not even heard of this functionality in CSS before,
> but I had a look at  https://css-tricks.com/snippets/css/a-guide-to-flexbox/,
> and it says this about justify-content:
>
> Note that that browser support for these values is nuanced. For
> example, space-between never got support from some versions of Edge,
> and start/end/left/right aren’t in Chrome yet. MDN has detailed
> charts. The safest values are flex-start, flex-end, and center.

It looks just as well without the justify-content property, so I've
just removed it entirely.

Julien.