The outline surrounding the buttons or links is hardly visible when using the keyboard for navigation

[cipriansv]

Browser / Version: Firefox Nightly 81.0a1 (2020-09-17) Operating System: macOS 10.15.6

Steps to Reproduce:

1. Navigate to https://webcompat.com/issues/new
2. Using "Tab" key, navigate to the URL field and fill it in.
3. Using "Tab" key, navigate to "Confirm" button.
4. Observe the button's outline.

Expected Behavior: The button outline is visible.

Actual Behavior: The button outline is hardly visible, making it difficult to see if the button is in focus.

Notes:

1. Screenshots attached.
2. The issue is not reproducible on Chrome 85.0.4183.102.
3. The issue is also reproducible for the links from the page.