refs. https://linear.app/tryghost/issue/DES-122/bookmark-card-issues
This PR addresses the following content card related problems:
1. The design of the following cards are more self-contained so it makes
more sense to use `px` for their font-sizes and spacings so it looks the
same regardless of the theme. Of course themes still can override these
values.
Updated cards to use `px` for font sizing:
- audio
- bookmark
- file
- product
2. So far header and signup cards had been using `rem` for font-sizes
and some sizing. This commit updates these to use `em` instead so that
it's consistent with all other cards.
3. The favicon sometimes is not available for bookmark cards. This PR also
fixes that by providing a default favicon for these cases.
8f3617aaa8