`, ``, or `` wrapper — regardless of class name (`.section__head`, `.workbench__head`, `.pricing__head`, `.catches__head`, `.foo__intro`, anything macrostructure- or section-specific)** — that contains both an eyebrow / label / number / kicker element AND a heading element MUST resolve to single-column layout: `display: block`, `display: flex; flex-direction: column`, or `display: grid; grid-template-columns: 1fr` (or `minmax(0, 1fr)`). Any multi-column grid on such a wrapper (`grid-template-columns: 1fr 2fr`, `minmax(0, 0.4fr) minmax(0, 1fr)`, `auto 1fr`, etc.) is banned. **The rule binds on the *content shape* — eyebrow + heading in the same wrapper — not on a specific class-name allowlist.** It supersedes the "Left-margin" axis in [`structure.md`](structure.md) and the "Hanging headers" pattern in [`layout-and-space.md`](layout-and-space.md) for any head that carries an eyebrow. **NOT bypassable by "preserve structural parity" / "mirror this reference" / "match the prior build" instructions** — if a reference build ships the banned pattern (most pre-rule-66 builds do), silently flatten it in the new build. The rules win over parity. Reference builds may pre-date this gate; the gate is authoritative.
67. **All-caps display heads with line-height < 1.0 → cap-collision on wrap.** Does any display-size element (`.hero__display`, `.section__title`, `h1`, `h2`, or anything `≥ --text-2xl`) declare both `text-transform: uppercase` AND a `line-height` (or `--lh-tight`) below `1.0`? If yes, fail. Uppercase glyphs have no descenders and their cap-tops sit at the very top of the line box — at `line-height: 0.94` (the old Manifesto / Sport / Brutal default) the cap-tops of line N+1 visibly collide with the baseline or commas of line N when the title wraps. The condensed display faces (Anton, Inter Tight 900, Bebas Neue) make this worse. **Floor for all-caps display heads is `line-height: 1.0`; recommended `1.02–1.08`.** Either bump `--lh-tight` ≥ 1.0 for the theme, or drop `text-transform: uppercase` on the display element. Most visible when a two-line `.section__title` wraps with a trailing comma on line one ("SAME PROMPT, TWO / DIFFERENT OUTPUTS.") — the comma + cap-D fuse into a single glyph blob.