2 files changed, 35 insertions, 1 deletions
diff --git a/src/features/layout/logic/marker.test.ts b/src/features/layout/logic/marker.test.ts
index d9e3826..53b91b0 100644
--- a/src/features/layout/logic/marker.test.ts
+++ b/src/features/layout/logic/marker.test.ts
@@ -1,5 +1,6 @@
+import type { TileMarker } from "@dispatch/layout-contract";
 import { describe, expect, it } from "vitest";
-import { markerOutline } from "./marker";
+import { markerOutline, markerStyle } from "./marker";
 
 describe("markerOutline — the diagnostic tile-border mapping", () => {
   it("main → a 4px solid red outline (the main tile's marker)", () => {
@@ -14,3 +15,15 @@ describe("markerOutline — the diagnostic tile-border mapping", () => {
     expect(markerOutline(undefined)).toBeUndefined();
   });
 });
+
+describe("markerStyle — the complete inline style (outline + inset offset)", () => {
+  it("insets the outline so it draws INSIDE the tile's box (never clipped at screen edges)", () => {
+    expect(markerStyle("main")).toBe("outline: 4px solid red; outline-offset: -4px");
+    expect(markerStyle("side")).toBe("outline: 4px solid green; outline-offset: -4px");
+  });
+
+  it("no/unknown marker → NO style at all (unmarked nodes carry zero outline CSS)", () => {
+    expect(markerStyle(undefined)).toBeUndefined();
+    expect(markerStyle("purple" as unknown as TileMarker)).toBeUndefined();
+  });
+});
diff --git a/src/features/layout/logic/marker.ts b/src/features/layout/logic/marker.ts
index eb1ff84..46259e0 100644
--- a/src/features/layout/logic/marker.ts
+++ b/src/features/layout/logic/marker.ts
@@ -10,6 +10,12 @@
  * (not a border) is used so the diagnostic draws WITHOUT changing any
  * tile's layout/size (4px solid, clearly visible).
  *
+ * The outline is INSET (`outline-offset: -4px`) so it draws INSIDE the
+ * tile's box: tiles span their containers edge-to-edge, so the default
+ * (outside) outline overflows the visible area and is clipped away at the
+ * screen edges. The views inside the tiles have no opaque full-bleed
+ * background, so the inset ring stays on top of the tile's content.
+ *
  * The marker is purely presentational: unknown/absent → no outline
  * (existing trees render exactly as before), and no other behavior is
  * attached to it anywhere in the renderer.
@@ -23,3 +29,18 @@ export function markerOutline(marker: TileMarker | undefined): string | undefine
   if (marker === "side") return "4px solid green";
   return undefined;
 }
+
+/** The inset that keeps the outline INSIDE the tile's box (see the header note). */
+export const MARKER_OUTLINE_OFFSET = "-4px";
+
+/**
+ * The COMPLETE inline style for a marked element — outline + inset offset in
+ * one declaration — or `undefined` when unmarked/unknown, so unmarked nodes
+ * carry no outline CSS at all (existing trees render exactly as before).
+ */
+export function markerStyle(marker: TileMarker | undefined): string | undefined {
+  const outline = markerOutline(marker);
+  return outline === undefined
+    ? undefined
+    : `outline: ${outline}; outline-offset: ${MARKER_OUTLINE_OFFSET}`;
+}