TwenyTwenty: wrong button color for style outline with WordPress 6.9

[threadi]

There is a problem with the button block in the TwentyTwenty theme when using the outline style. The background color is set incorrectly.

In WP 6.8.3:

:root :where(.wp-block-button.is-style-outline--2 .wp-block-button__link) {
  background: transparent none;
}

In WP 6.9:

button, .button, .faux-button, .wp-block-button__link, .wp-block-file .wp-block-file__button, input[type=“button”], input[type=‘reset’], input[type=“submit”], .bg-accent, .bg-accent-hover:hover, .bg-accent-hover:focus, :root .has-accent-background-color, .comment-reply-link {
  background-color: #cd2653;
}

This can also be reproduced in the Playground:

1. Go to ​https://playground.wordpress.net.
2. Search for Themes > Add Theme > TwentyTwenty, install & activate.
3. Edit Page > Sample Page
4. Add a button block there and give it any text you like. Then select “Outline” on the right under Styles.
5. Save and check.

Result:

• View in the editor is correct.
• View in the frontend is incorrect.

[swissspidy]

We're already tracking this in #64354

[westonruter]

I added the description to the other ticket: #64354