Describe the bug
In the WordPress 5.5 block editor, the "Save draft", "Switch to draft", and "Preview" buttons have been restyled and in their normal state they now look like plain text.

For accessibility, and I'd say also for a good UI, they should be styled in a way that they can be identified as user interface controls at first glance.

In WordPress 5.4, they weren't perfect either but at least:

• the "Save draft" button, although it missed a shape or an underline, had blue text: blue is a well established convention in WordPress for interactive controls
• same for the "Switch to draft" button
• the "Preview" button looked like a button, which was OK

Screenshots:

Instead, now in WordPress 5.5 they look like plain text:

• in their normal state, there's no shape or underline to identify them as buttons
• the buttons text color is a dark grey #1e1e1e which makes them look as plain text

Screenshots:

Recommended:

• either restore the blue color and add an underline
• or, preferably, make them look like buttons, because that's what they are