Flatten the selection and the menu highlight; kill the Aero afterglow

Three things looked wrong, three different causes.

The selected row carried a border. 7.css outlines tr.highlighted (#aaddfa) on
top of its fill, and we had been restating that outline in the new blue — so
the band had an edge, and on the cursor row the dotted focus rect made three
concentric outlines around a single row. The reserved 1px border stays (it is
what stops selection from shifting rows) but is transparent in every state;
the fill paints under it, since background-clip is border-box. --w7-sel-bd and
--w7-sel-bd-idle are gone with it.

The context menu highlighted items with 7.css's translucent gradient wash —
the same gradient the ListView selection just dropped. It now uses
--w7-sel-bg, so selection reads identically wherever it appears.

The hover-off animation was button.css bleeding into menu items, which ARE
buttons: button::before is a glow overlay that fades out over a full second,
and menu.css suppresses it with content:none on the :hover arm ONLY — so
leaving an item brought the pseudo back with opacity animating 1 -> 0, a ghost
trailing the pointer. Killing content in every state removes it. Same family,
also fixed: button:focus runs pulse-anim infinitely, and this menu moves real
focus between items for keyboard nav.

menu-probe.ts now checks the highlight too, using hover-probe's :hover ->
.simhover rewrite: it measures colour spread down a text-free strip of a
force-hovered item, so "is it flat?" is a measurement. Verified the check can
fail by injecting the old wash into the built stylesheet — spread 9, exit 2;
the flat fill reads spread 0 at exactly #cbe8f6. The harness lost its
selection outlines and nothing else, in both themes.

Co-Authored-By: Claude <noreply@anthropic.com>

docs/architecture.md

@@ -429,12 +429,17 @@ zeroed); the frame reads the state off its own child with
 existing `maximized` signal rather than subscribing to `windowState` twice.
 
 **Selection band**: the file list's selected row is a FLAT Win7-Explorer blue
-(`--w7-sel-bg/-bd` = `#cbe8f6`/`#26a0da`), not 7.css's `--w7-el-grad-h` — that
-var is its Aero element-hover ramp and stays reserved for buttons and tabs,
-which still want the gloss. The unfocused pane gets `--w7-sel-bg-idle/-bd-idle`,
-Explorer's grey inactive selection; the band never disappears with focus, only
-weakens (the commander convention above). All four are dark-overridden in BOTH
-dark blocks.
+(`--w7-sel-bg`, `#cbe8f6`) with **no border** — not 7.css's `--w7-el-grad-h`,
+which is its Aero element-hover ramp and stays reserved for buttons and tabs
+that still want the gloss, and not its `#aaddfa` row outline, which stacked a
+second edge inside the fill and, with the cursor row's dotted rect, drew three
+concentric outlines on one row. Every row still reserves `border: 1px solid
+transparent` for geometry; the fill paints under it (`background-clip`
+defaults to `border-box`). The unfocused pane gets `--w7-sel-bg-idle`,
+Explorer's grey inactive selection — the band never disappears with focus,
+only weakens (the commander convention above). Both are dark-overridden in
+BOTH dark blocks. The context menu's item highlight uses the same
+`--w7-sel-bg`, so selection reads identically wherever it appears.
 
 **Context menu**: pure 7.css via its real menu contract —
 `ul[role=menu] > li[role=menuitem] > button` for actions,
@@ -446,9 +451,13 @@ one (`dist/gui/menu.css`), including the gutter stripe, disabled state and
 submenu arrows. Keyboard moves REAL focus between items (7.css styles
 `:focus-visible` like `:hover`); Enter/Space activate buttons natively. Only
 menu.css's hardcoded light literals are restated for dark, in `skinfix` — plus
-one structural override: `.w7-ctx` restores `position: fixed`, which 7.css's own
-`position: relative` on `ul[role=menu]` had been silently winning (see
-gotchas.md; `scripts/menu-probe.ts` is the regression test).
+three overrides keyed on the app's own `w7-ctx` marker: `position: fixed`
+(7.css's `position: relative` on `ul[role=menu]` had been silently winning),
+the flat `--w7-sel-bg` highlight in place of its gradient wash, and
+`content: none` on the item buttons' pseudo-elements, which kills both the
+1s Aero afterglow and the infinite `pulse-anim` on a focused item (see
+gotchas.md). `scripts/menu-probe.ts` regression-tests placement AND highlight
+flatness, each with a control that proves the check can fail.
 
 **Font**: Segoe UI is absent off Windows and not redistributable. Noto Sans —
 the substitute 7.css itself names — is vendored (OFL-1.1, from

docs/gotchas.md

@@ -176,6 +176,20 @@ touching the adjacent code.
   bug**: nothing about the idle window changes. `scripts/menu-probe.ts` renders
   the menu at declared coordinates and scans whether it landed there, with a
   marker-less control menu as its own discriminator.
+- **7.css's button effects reach anything that IS a button — including menu
+  items — and one of them fades out over a FULL SECOND.** `button::before` is
+  an Aero glow overlay with `opacity: 0`, raised to 1 on hover, and
+  `button:not(:hover):before` carries `transition: opacity 1s linear`.
+  menu.css suppresses it with `content: none` on the **`:hover` arm only**, so
+  while an item is hovered nothing paints, but the moment the pointer leaves,
+  the pseudo returns with opacity animating 1 → 0: a blue ghost trailing the
+  cursor down the menu. Killing `content` in *every* state is the fix —
+  suppressing the transition alone leaves a glow that simply snaps. Two more
+  from the same family: `button:focus` runs `pulse-anim` *infinitely*
+  (`1s ease infinite alternate`), which matters because the context menu moves
+  REAL focus between items for keyboard nav, and the hover paint is 7.css's
+  translucent gradient wash — the same one the ListView selection dropped.
+  All three are overridden together, scoped to `w7-ctx`.
 - **Its selectors are exact, and a near-miss looks exactly like "7.css doesn't
   support this".** `menu[role=tablist] button` is a DESCENDANT selector, so
   every button inside the strip becomes a tab — the `+` and the right-hand