Revise styling of special buttons

[kra-mo]

Special buttons (Success, Warning, Error) currently derive from primary-style buttons. This is often way more inviting than these actions should be.

Instead, Warning and Error should be derivative of secondary actions, as that is most often what they are. Keep the destructive styling, but remove the screaming :)

The one question is Success. It is used less than the others, but when used, it seems to be the primary action. As such, I'm keen on keeping the existing styling for it, but maybe someone can provide more context on its usage.

I would attach mockups but attachments on GitHub once again don't work.

cc @nextcloud/designers

Colors

Success (if we decide to use them)

Light

• fg: #005416
• bg: #D5F2DC

Contrast: 7.67 (AAA)

Dark

• fg: #D5F2DC
• bg: #11321A

Contrast: 11.79 (AAA)

Warning

Light

• fg: #664700
• bg: #FFEEC5

Contrast: 7.46 (AAA)

Dark

• fg: #FFEEC5
• bg: #3D3114

Contrast: 11.18 (AAA)

Error

Light

• fg: #8A0000
• bg: #FFCCCC

Contrast: 7.1 (AAA)

Dark

• fg: #FFCCCC
• bg: #612525

Contrast: 8.17 (AAA)

[susnux]

An alternative could be outlined buttons which we also discussed in the past:

But thats pure design decision, I personally do not like our current they are too annoying but like both other :)
BTW we do not need new color variables, we already have those colors defined for e.g. NcNoteCard and similar.

[kra-mo]

I personally think that the non-outline one is more in our style. It's nice that no color variables are needed!