Cherry-pick of 2ced31e81d adapted to Forgejo releases UI.
Percentage-based `border-radius` [creates undesirable
ellipse](https://jsfiddle.net/silverwind/j9ko5wnt/4/) on non-square
content. Instead, use pixel value and use same wording `full` like
tailwind does, but increast to 99999px over their 9999px.
(cherry picked from commit 2ced31e81dd9e45659660c1abff529d0192fd8ed)
Adapted by @0ko
(cherry picked from commit afa1380672)
(cherry picked from commit 7b7318255e68ee7e4d0f5b1b8e5ef91cd72a59e5)
def21375b7