HoC.com - Update UI on activity tiles - #48080

Just to capture what we discussed:

• The vertical spacing between tiles can match the horizontal spacing.
• Ideally, we wouldn't need grey borders around the tile images, especially since some images already have their own borders. In the past, for similar tiles, we've been able to limit the grey border to the text area below. However, since some tutorials have white backgrounds, it seems we'll need to draw the grey border around all images.
• Currently, the majority of tiles have a lot of whitespace below the text. A few tutorials have multi-line "detail strings" (as generated here) but our idea is to truncate them and to work with @ericfershtman to reduce them to something shorter in the gsheet. This way, we can adjust the tile size to suit the majority of tutorials.

For reference, grey border only around text:

Grey border around image: