The bar is three groups now: how you are looking at it, at what width, and what to do with it. The
middle is centred against the BAR rather than against its neighbours, because the outer two change
width as sections come and go and a middle that drifted with them would never be in the same place
twice.
A section OPTS IN, the same way it opts into Save. Most have no preview — Media is a file browser,
Administration is a connection form, Messages is an inbox — and offering to view any of them at tablet
width offers something that means nothing. A control that does nothing teaches people that controls do
nothing.
The widths are REAL viewport sizes and the frame is SCALED to fit, never squeezed into whatever the
panel has. That distinction is the whole point: an iframe given the panel's width has the site's own
media queries answering the PANEL's size, so "Desktop" in a narrow panel renders the tablet layout and
labels it desktop — the one thing a preview must not do. Never scaled up either: a 390px phone blown
up to fill a wide panel is a phone nobody has, and every judgement made against it is wrong in the
direction of "looks fine".
390 is the iPhone width slots.ts already assumes. 834 is iPad portrait, deliberately above the site's
md: breakpoint at 768 so it shows the desktop nav rather than the drawer — 768 exactly sits on the
boundary and is the least informative width available. 1440 is past the 1280 the content column caps
at, so the margins either side are visible rather than implied.
View gives the preview the whole panel. That is what makes it worth having: at edit height a phone is
a letterbox, and a phone is the width somebody most wants to look at properly.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
pastilhasandClaude Opus 5
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