Apply border to primary button if on log in page (and not in a dark container) or if in header

[jancborchardt]

fix #12294, please review @nextcloud/designers @schiessle

For buttons on dark background, like in the header of the share page, there still is white border:

For buttons elsewhere in the main content, where they are on white background, the border color is the same as the background color:

We could also go with border:none; which looks even better, but then also need an exception for theming:

In general we still need something for light theming colors … as usual. @juliushaertl @skjnldsv any idea? Maybe again cap the color at a specific lightness and then use the standard border color?

I am not sure whether this is something for 15 in any case as this has a bunch of potential for regressions and looking strange too.

[skjnldsv]

In general we still need something for light theming colors … as usual. @juliushaertl @skjnldsv any idea? Maybe again cap the color at a specific lightness and then use the standard border color?

I'll suggest a translucent border (#0003) for light colours. It should automatically apply the background as primary.

[jancborchardt]

@skjnldsv could you add a commit to implement that, or give me a pointer for this?

[skjnldsv]

@jancborchardt sure, you need to do it on the theming scss. :)
If inverted: border-color: rgba(0,0,0,0.3)

[jancborchardt]

@skjnldsv done, I think. :) Thanks for the pointer!

[jancborchardt]

@schiessle @MariusBluem @juliushaertl @MorrisJobke as you were involved in the "blurry buttons" issue, your review is very welcome! :)

[MorrisJobke]

Tested and looks a lot better than before 👍