What steps will reproduce the problem?
(1) Focus any focusable element
(2) Observe the focus ring

What is the expected result?

Focus ring should be clearly visible.

What happens instead?

Focus ring may be difficult to discern. 

Anecdotal user reports:
"Browser defaults [for the focus ring style] in Chrome, for example, are so bad that I rarely see them myself. (Not 20/20 vision, but quite good while wearing glasses)"
"The default in Chrome is so bad we’ve been accidentally failing things in [accessibility] test as not having a focus state because we couldn’t see it ourselves"

Once :focus-visible selector is available, we should redesign the default focus ring to be more clearly visible, and show only on :focus-visible state.