- if that item is "display: table-cell", it must be within a larger element that's "display: table" or "display: table-row"
- "vertical-align: middle" works also for inline-block elements, but that means it's subject to all the other gotchas present in the article about explicit sizing
It eventually makes a kind of sense, but these rules are passed down in folklore and trial-and-error.
Your first point isn’t correct: if you have a solitary element with display:table-cell it’ll generate the appropriate anonymous elements needed for display.
