[Snackbar] Shouldn't be light in dark mode

[manufont]

• The issue is present in the latest release.
• I have searched the issues of this repository and believe that this is not a duplicate.

Current Behavior 😯

In dark mode, snackbar have a white background and a dark color. However, snackbar actions seems to have the same style as if they were not part of a snackbar. This means that disabled actions appears white on a white background.

Expected Behavior 🤔

Disabled snackbar actions should be visible on dark mode.

Steps to Reproduce 🕹

https://codesandbox.io/s/material-ui-issue-forked-9zlxc

Steps:

1. Configure a custom theme with dark mode enabled
2. Display a Snackbar with a disabled action

[oliviertassinari]

@manufont I'm tempted to say that we can ignore your issue because if the action is disabled, it shouldn't be shown in the first place in a toast.

Now, having a closer look at the Material Design guidelines, I believe the snackbar should be dark, not light. At least; it's the behavior I could find on:

• YouTube
• Google Keep

This would also solve the contrast issue between the action button color and background.

[Renfrew]

Can I work on this?

[oliviertassinari]

@ManuFront you could provide a light theme to the button https://codesandbox.io/s/material-ui-issue-forked-ucdv8?file=/src/Demo.js but it would only likely hide the root issue. I would encourage to either customize the button or to not render a disabled one inside the snackbar (what's the use case if it can't be interacted with)?

https://material.io/design/color/dark-theme.html#ui-application