When using relative paths for CSS resources (such as background images),
`@angular/cli` will move them to the root `dist/` directory (and update
the paths in CSS accordingly). This results in the SW being unable to
cache the resource, because it is not where it expects it to be.
This commit fixes this issue for the footer background image, by using
an absolute path for the URL. (It also removes an unused style that
would have been affected by the same issue.)
PR Close#27250
271fcb0f3e