diff --git a/web/src/main.ts b/web/src/main.ts
index f87a3dd..dfe8518 100644
--- a/web/src/main.ts
+++ b/web/src/main.ts
@@ -33,7 +33,7 @@ import { createRecenterControl } from "./ui/recenter.ts";
 import { getWebApp } from "./telegram/webapp.ts";
 import { watchTheme } from "./telegram/theme.ts";
 import { wireBackButton } from "./telegram/backbutton.ts";
-import { resolveSafeInsets, applySafeArea } from "./telegram/safe-area.ts";
+import { resolveSafeInsets, applySafeArea, watchSafeAreaChanges } from "./telegram/safe-area.ts";
 import { createSession } from "./session/client.ts";
 import { getSession, isSessionStale } from "./session/store.ts";
 import { acquireFix, isFixStale, fixAgeSeconds } from "./location/chain.ts";
@@ -72,6 +72,11 @@ void boot();
 async function boot(): Promise<void> {
   // 1 — safe-area vars are set before any layout reads them (PX-03 groundwork).
   applySafeArea(resolveSafeInsets(getWebApp()));
+  // PX-04/D-03: the insets re-resolve at RUNTIME too — rotation and fullscreen
+  // transitions re-apply through the same union authority on the client's
+  // inset events. Same one-shot getWebApp() value as the apply line above;
+  // internally guarded (null WebApp / missing onEvent → returns immediately).
+  watchSafeAreaChanges(getWebApp());
 
   // 3 (declared ahead of their first use inside the closures below) — the
   //    single-shell state the BackButton resolver and the stale branch read:
diff --git a/web/src/route/route.ts b/web/src/route/route.ts
index 4389456..65e8256 100644
--- a/web/src/route/route.ts
+++ b/web/src/route/route.ts
@@ -60,6 +60,7 @@ import { clearRouteLayers, setRouteDrawn } from "./route-layers.ts";
 import type { buildRouteCard, buildRoutePendingCard } from "./route-card.ts";
 import { createGuidanceCamera } from "../guidance/camera.ts";
 import { engageCloseProtection, releaseCloseProtection } from "../guidance/close-protection.ts";
+import { requestGuidanceFullscreen, exitGuidanceFullscreen, watchFullscreenEvents } from "../telegram/fullscreen.ts";
 import { fireHaptic } from "../guidance/haptics.ts";
 import {
   buildConfirmCard,
@@ -339,6 +340,10 @@ export function createRouteController(deps: RouteControllerDeps): {
     if (g === null || g.active) return;
     g.active = true;
     engageCloseProtection(deps.wa ?? null);
+    // PX-04/D-03: the native fullscreen request is BEST EFFORT — a refusal is a supported fallback, never a guidance failure.
+    requestGuidanceFullscreen(deps.wa ?? null);
+    // PX-04/D-03: the fullscreen events are observability only — no state, no logging (D-14 category-only law).
+    watchFullscreenEvents(deps.wa ?? null, () => { /* observability only — no state, no logging */ });
     if (deps.shellRoot !== undefined) deps.shellRoot.dataset.guidance = "active";
     foldEta(g);
     camera.easeToSnapped(g.lastSnapped); // the locked-follow pose over the SNAPPED line
@@ -479,6 +484,8 @@ export function createRouteController(deps: RouteControllerDeps): {
     stopWatch();
     deleteEnvelope();
     releaseCloseProtection(deps.wa ?? null);
+    // PX-04/D-03: the trip end releases fullscreen alongside the close protection — best effort, same law.
+    exitGuidanceFullscreen(deps.wa ?? null);
     if (deps.shellRoot !== undefined) delete deps.shellRoot.dataset.guidance;
     stopBlink();
     if (deps.bannerHost !== undefined) deps.bannerHost.replaceChildren();
@@ -614,6 +621,8 @@ export function createRouteController(deps: RouteControllerDeps): {
     };
     envelopeId = trip.envelopeId;
     engageCloseProtection(deps.wa ?? null);
+    // PX-04/D-03: a resumed trip is a live guidance session — the same best-effort fullscreen request as a fresh start.
+    requestGuidanceFullscreen(deps.wa ?? null);
     if (deps.shellRoot !== undefined) deps.shellRoot.dataset.guidance = "active";
     setRouteDrawn(deps.map, { points: trip.model.points }, []);
     const first = points[0];
@@ -690,6 +699,8 @@ export function createRouteController(deps: RouteControllerDeps): {
     stopWatch();
     if (guidance === null) return;
     releaseCloseProtection(deps.wa ?? null);
+    // PX-04/D-03: the walk-back teardown releases fullscreen alongside the close protection.
+    exitGuidanceFullscreen(deps.wa ?? null);
     if (deps.shellRoot !== undefined) delete deps.shellRoot.dataset.guidance;
     stopBlink();
     if (deps.bannerHost !== undefined) deps.bannerHost.replaceChildren();