Pale bands = the SPA's 6-column grid (real token widths). Goal: in the macOS embedded webview, drop the orange rails (and their close-X / drag affordances) so the webview content reclaims the full width, while keeping every keyline that a panel legitimately needs when open. Browser keeps everything as-is.
Keyline ownership (closed): the left keyline is the toc-rail's
border-right at x≈36; the right keyline is the tag-rail's
border-left. Both lines exist only because the rail exists. Remove the rail and these lines vanish — which is what we want, since native chrome draws the edge.
The travelling keyline: opening animates grid-template-columns
(rail 36→0, panel 0→280) over 75ms. The panel's own border-right rides its
growing right edge — the keyline slides from x≈0 to x≈280 like a curtain rod. No separate
keyline element exists; each panel carries its own. This is why removal is clean: a closed
0-width panel shows no line; an open panel brings its line with it.
Issue ① — left edge: the native NSSplitView divider (grey) is now
the only left edge. The webview content starts at its own x=0 + --bn-gutter-left: 2rem.
No web keyline needed — good. But verify there's no double divider (native divider + a stray
web border).
Issue ② — right edge: with the tag-rail gone, the minimap becomes the
rightmost element. Its only margin from the window edge is padding: 0 0.75rem. And on
non-Quotes tabs (no minimap) the center's right margin is just --bn-gutter-right: 0.5rem
(≈8px) — that gutter was sized assuming a 36px rail sat beyond it. The webview fills the pane to the
window edge (macOS adds no inset), so content would sit ~8px off the glass. Likely want to bump
--bn-gutter-right in embedded mode for symmetric breathing room.
Issue ③ — scrollbar gutter: tag-rail carried margin-right:8px
and tag-sidebar padding-bottom:2rem "to clear the macOS auto-hiding scrollbar".
Those hacks disappear with the rail; confirm the overlay scrollbar (now floating over the minimap /
content edge) auto-hides cleanly and doesn't clip the last row.
Keyline (open): the toc-sidebar brings its border-right
(at x≈280) — needed, separates the in-report Contents list from the quotes. Its left edge sits
at webview x=0 against the native split divider. Result is a legit macOS three-pane: native project
list → divider → web Contents → keyline → quotes (Mail / Notes idiom). The web panel's left edge
must not draw its own border or you double the divider.
Removed affordances: no rail icon (toolbar replaces it), no close-X
(toolbar toggle + [ key close it), no rail drag-to-open, and overlay/hover-peek mode
disappears entirely — it was reachable only through the rail. Desktop TOC becomes a clean two-state
closed↔push, matching the tag side and native NSSplitView semantics.