• This should be 12px, since it is the first list item
• This should be 16px; it has an adjacent, preceding list item
• This should be 16px; it has an adjacent, preceding list item
• This should be 16px; it has an adjacent, preceding list item
• This should be 16px; it has an adjacent, preceding list item

1. This should be 12px, since it is the first list item
2. This should be 12px, since it only has one adjacent list item preceding it
3. This should be 18px; it has two adjacent, preceding list items
4. This should be 18px; it has two adjacent, preceding list items
5. This should be 18px; it has two adjacent, preceding list items