[Showcases] Adapt `Glass Card` for Light color themes

[stdword]

reference: https://github.com/stdword/logseq13-full-house-plugin/discussions/9#discussioncomment-5595837

If you are waiting for this task:

• Please add 👀 reaction so I can prioritise it over other features
• You can subscribe for notifications on this issue

[stdword]

Adapted to any DARK theme colors

white colors: TBD