diff --git a/src/lib/pwa/pwa_install.svelte.ts b/src/lib/pwa/pwa_install.svelte.ts
index f999b327..a80c6620 100644
--- a/src/lib/pwa/pwa_install.svelte.ts
+++ b/src/lib/pwa/pwa_install.svelte.ts
@@ -5,11 +5,14 @@
  *
  * Usage:
  *   - Call `pwa_install.init()` once in the root +layout.svelte (browser $effect).
+ *     init() handles dismiss state and standalone detection (needs localStorage/DOM).
  *   - Import `pwa_install` in any component to read state and trigger the prompt.
  *
  * Platform behaviour:
- *   - Chrome / Android / Desktop Chrome: intercepts `beforeinstallprompt`,
- *     lets us show a custom button that calls the native install flow.
+ *   - Chrome / Chromium / Android: intercepts `beforeinstallprompt` at module load time
+ *     (critical — the event fires very early, before $effects run). Shows a custom button.
+ *   - Firefox desktop: does NOT support `beforeinstallprompt`. Firefox provides its own
+ *     install button in the address bar when a valid manifest + service worker are present.
  *   - iOS Safari: `beforeinstallprompt` never fires; we detect iOS + not-standalone
  *     and show manual "Share → Add to Home Screen" instructions instead.
  *   - If already running in standalone mode (i.e. already installed) → hide everything.
@@ -33,6 +36,21 @@ let _is_installed = $state(false);
 let _is_dismissed = $state(false);
 let _initialized = false; // plain boolean — not reactive, guards against double-init
 
+// --- Early event capture (module load time) ---
+// `beforeinstallprompt` fires within ~1 second of page load — before any $effect runs.
+// Register here so we never miss it regardless of when init() is called.
+if (browser) {
+    window.addEventListener('beforeinstallprompt', (e) => {
+        e.preventDefault();
+        _deferred_prompt = e as BeforeInstallPromptEvent;
+    });
+
+    window.addEventListener('appinstalled', () => {
+        _is_installed = true;
+        _deferred_prompt = null;
+    });
+}
+
 // --- Private helpers (SSR-safe) ---
 
 function _in_standalone(): boolean {
@@ -83,7 +101,10 @@ export const pwa_install = {
     },
 
     /**
-     * Register browser event listeners. Call ONCE from root +layout.svelte.
+     * Finish initialisation after the layout mounts. Call ONCE from root +layout.svelte.
+     * Handles dismiss state (needs localStorage) and standalone detection (needs DOM).
+     * Event listeners for beforeinstallprompt/appinstalled are already registered at
+     * module load time — this does NOT register them again.
      * Safe to call multiple times (idempotent).
      */
     init(): void {
@@ -107,18 +128,6 @@ export const pwa_install = {
                 localStorage.removeItem(DISMISS_KEY);
             }
         }
-
-        // Capture the deferred install prompt (Chrome/Android/Desktop Chrome).
-        window.addEventListener('beforeinstallprompt', (e) => {
-            e.preventDefault();
-            _deferred_prompt = e as BeforeInstallPromptEvent;
-        });
-
-        // Fired by the browser after the user accepts the install prompt.
-        window.addEventListener('appinstalled', () => {
-            _is_installed = true;
-            _deferred_prompt = null;
-        });
     },
 
     /** Trigger the native install prompt. No-op if no deferred prompt is available. */