Should a Section-tag Div be resizable, or always a full-width band?

The question: In the modern layout model every box is one primitive — a Div you tag section / div / article / aside — so the Width control was offered on all of them, including a Div tagged <section>. That let you make a section 5/6 wide. The classic Section never could. Is a resizable section correct, or should a Section always be a full-width band?

Context

A <section> is the page's band primitive — the full-bleed horizontal region you start a layout with. In the uniform Div model it's just a Div with the section tag, and every Div exposes a per-device Width (twelfths / fifths / content-sizing / custom) plus a Content Width (constrain + centre the content inside a full-width band).

The two controls do very different things:

• Width sizes the box as a flex item — it makes the whole band narrower and left-aligned (it's a fraction of the parent, hugging the start edge).
• Content Width keeps the band full-width and centres its content to a max-width — the band-with-a-container pattern. A section-tag Div already does this automatically at the site width.

So a fractional Width on a section produces a narrow, off-centre band — almost never what anyone intends, and something the classic Section (always full-width, container inside) never allowed. The capability came from the uniform model, not from a deliberate "sections should be resizable" choice.

Options considered

• Leave Width on sections (fully uniform). Every Div behaves identically — power-user flexible. But it makes an accidental narrow/left-aligned band a single mis-click away, and it muddies the "section = band" mental model that the whole modern layout system is trying to teach.
• Hide Width only on root sections. A top-level band can't be sized; a section nested inside a flex row keeps Width (there it's a legit flex item). More flexible, but "does this control exist?" now depends on where the section sits — less predictable, and nesting a <section> inside a flex row is itself an unusual thing to do.
• Hide Width on all sections (chosen). A section-tag Div is always full-width. Width is hidden in the editor and any stored Width is ignored on the front end; Content Width is the tool for constraining a band's content. Width stays on div / article / aside, which are genuine columns / flex items.

Decision

Hide the Width control whenever the Div's tag is section, and ignore any stored Width for a section on render. A Section is always a full-width band, matching the classic Section. To make a band's content narrower, use Content Width (which keeps the band full-width and centres the content). div / article / aside Divs keep Width — they're the columns and flex items.

Implementation: the front-end view neutralises width when tag === 'section' (one guard, so no fw-span class and no scoped width rule are emitted); the editor skips mounting the width stepper for a section and forces the canvas preview to full-width.

Why

• Semantics over uniformity. The point of the section tag is "this is a band." A control that contradicts that — turning the band into a narrow left-aligned strip — is a footgun, not a feature. The one place a fractional width is meaningful (a box in a row) is exactly what div is for.
• There's already a right tool. Content Width covers the only sane reason to want a "narrower" section (a contained, centred content column in a full-bleed band), and does it correctly. Two controls that look similar but behave oppositely is worse than one clear one.
• Consistency with the classic Section keeps the two models interchangeable in users' heads and avoids "why did my section go narrow and slide left?" support cases.