Detecting that ad has failed to load with timeout is not accurate and
won't work on slow connections. This commit fixes that by changing
detection to use 'onerror' event on <script> tag instead, which will be
triggered if ad script fails to load due to blocking.
- Now styled as a proper link.
- Change :focus to :focus-visible to avoid link getting stuck in that
'hovered' state because focus does not actually change (it deffo
should though, something to fix in the future - should be one
fragment change).
- Removed all padding and transition.
Sasha Sorokin