Accessibility: The buttons 'Copy', 'Expand All', and 'Collapse All' in the Response Samples lack sufficient focus visibility

[saskiaw]

Describe the bug
The buttons 'Copy', 'Expand All', and 'Collapse All' in the Response Samples lack sufficient focus visibility. The grey focus indicator has a contrast ratio of 1.3:1 against the background. Additionally, the focus border around the 'GET' above the Response Samples is also problematic. The difference in contrast is barely perceptible and certainly not 3:1.

Expected behavior
We expect that we have equal focus and it is simply displayed in white. You can indeed set the text color via the ThemeInterface, but I cannot adjust the behavior and the contrast.

Screenshots
without focus in Response samples:

with focus in Response samples: