Root plate: the toolkit's standard spec, and the edge inset that goes with it

The window's base is cce-ui's standard root plate (PaintCtx::root_plate)
in place of a hardcoded deep-slate quad of this app's own: the DE root
material at its opacity, the shared silhouette arc, the rolled rim. With
the rim real again, window_pad() is layout::root_plate_inset() — the
roll plus one padding, the toolkit's one number for where content starts
on a rolled root plate — so the run of flat face at each window edge is
the same padding the split leaves between the panes. Measured in a
shadow session at scale 2: 28 device px of flat face at the left and
bottom edges against 24 across the split, the 2px being where the
roll's ramp reads as finished before its nominal width.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

 src/main.rs | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index c567c21..2b8ddf5 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -627,22 +627,20 @@ fn save_emails_for_account(email: &str, emails: &[Email]) {
 }
 
 /// Inset from the WINDOW's outer edge to anything standing on the root
-/// plate. The same value as [`pane_pad`], deliberately: this window's base
-/// is a flat fill with no rolled rim (it paints a plain quad, not a root
-/// `PlateSpec` the way cce-files does), so the run of untouched plate at a
-/// window edge is exactly what the layout says, and one number makes every
-/// gap in the window read the same — rim to bar items, items to plates,
-/// plates to rim, and the split between the panes.
+/// plate: the toolkit's [`cce_ui::layout::root_plate_inset`], the plate's
+/// rolled rim plus one [`pane_pad`]. The padding is a run of flat plate
+/// face — the same run [`pane_gap`] leaves between the two panes — and the
+/// face only begins where the roll ends, so measured from the window edge
+/// the inset carries the roll too. That is what makes every gap in the
+/// window read the same: rim to bar items, items to plates, plates to rim,
+/// and the split between the panes.
 ///
-/// It used to add `bevel_width` (less a measured 1px optical trim) to make
-/// up for a rolled rim eating the first 9.3px, which was true of the window
-/// on 2026-09-19 and no longer is: with the roll gone the compensation
-/// alone was the discrepancy, 20px at the edges against 12 between the
-/// panes. If the window grows a rolled rim again, this is the one place to
-/// put the roll back — measured, not derived: screenshot, count columns of
-/// untouched plate, and compare with the gap between the panes.
+/// History: while this window's base was a flat quad with no rim (until
+/// 2026-09-24) the roll compensation alone was a 20-against-12 discrepancy,
+/// and the inset was briefly the bare padding. The base is the standard
+/// root plate now, and the roll is real again.
 fn window_pad() -> f32 {
-    pane_pad()
+    cce_ui::layout::root_plate_inset()
 }
 
 /// VISIBLE height of one menubar control — what you see, not the rect it is
@@ -5288,8 +5286,10 @@ impl Application for ClearEmailApp {
                 .collect()
         };
 
-        // 1. General window background (deep slate blue)
-        quads.push((0.0, 0.0, w_f32, h_f32, [0.05, 0.05, 0.07, 1.0]));
+        // 1. The standard root plate (cce-ui `PlateSpec::window`): the DE root
+        // material at its opacity, the shared silhouette arc, the rolled rim.
+        // Replaces a hardcoded deep-slate quad of this app's own.
+        quads.pc.root_plate(w_f32, h_f32);
 
         // Anything that must show THROUGH a frosted plate has to exist before
         // the FIRST blur plate in the frame: that one takes the backdrop