diff --git a/firebase/firebase.json b/firebase/firebase.json
index 9e6c256..2486f2f 100644
--- a/firebase/firebase.json
+++ b/firebase/firebase.json
@@ -19,20 +19,35 @@
     ],
     "headers": [
       {
-        "source": "**",
+        "source": "/index.html",
         "headers": [
-          { "key": "Cache-Control", "value": "no-cache" },
-          { "key": "X-Robots-Tag", "value": "noindex, nofollow" },
-          { "key": "X-Frame-Options", "value": "DENY" },
-          { "key": "X-Content-Type-Options", "value": "nosniff" },
-          { "key": "Referrer-Policy", "value": "strict-origin-when-cross-origin" },
-          { "key": "Permissions-Policy", "value": "camera=(), microphone=(), geolocation=(), payment=(), usb=()" }
+          { "key": "Cache-Control", "value": "no-store, no-cache, must-revalidate, max-age=0" },
+          { "key": "Pragma", "value": "no-cache" }
         ]
       },
       {
-        "source": "**/*.@(mjs|css|woff|woff2|ttf|otf|jpg|jpeg|gif|png|svg|webp|ico|avif)",
+        "source": "/sw.js",
         "headers": [
-          { "key": "Cache-Control", "value": "public, max-age=31536000, immutable" }
+          { "key": "Cache-Control", "value": "no-store, no-cache, must-revalidate, max-age=0" },
+          { "key": "Service-Worker-Allowed", "value": "/" }
+        ]
+      },
+      {
+        "source": "/registerSW.js",
+        "headers": [
+          { "key": "Cache-Control", "value": "no-store, no-cache, must-revalidate, max-age=0" }
+        ]
+      },
+      {
+        "source": "/workbox-*.js",
+        "headers": [
+          { "key": "Cache-Control", "value": "no-store, no-cache, must-revalidate, max-age=0" }
+        ]
+      },
+      {
+        "source": "/manifest.webmanifest",
+        "headers": [
+          { "key": "Cache-Control", "value": "no-store, no-cache, must-revalidate, max-age=0" }
         ]
       },
       {
@@ -40,6 +55,23 @@
         "headers": [
           { "key": "Cache-Control", "value": "public, max-age=31536000, immutable" }
         ]
+      },
+      {
+        "source": "**/*.@(mjs|css|woff|woff2|ttf|otf|jpg|jpeg|gif|png|svg|webp|ico|avif)",
+        "headers": [
+          { "key": "Cache-Control", "value": "public, max-age=31536000, immutable" }
+        ]
+      },
+      {
+        "source": "**",
+        "headers": [
+          { "key": "Cache-Control", "value": "no-store, no-cache, must-revalidate, max-age=0" },
+          { "key": "X-Robots-Tag", "value": "noindex, nofollow" },
+          { "key": "X-Frame-Options", "value": "DENY" },
+          { "key": "X-Content-Type-Options", "value": "nosniff" },
+          { "key": "Referrer-Policy", "value": "strict-origin-when-cross-origin" },
+          { "key": "Permissions-Policy", "value": "camera=(), microphone=(), geolocation=(), payment=(), usb=()" }
+        ]
       }
     ]
   }
diff --git a/src/app/app-bar.tsx b/src/app/app-bar.tsx
index e976bf4..9cf0c03 100644
--- a/src/app/app-bar.tsx
+++ b/src/app/app-bar.tsx
@@ -30,7 +30,13 @@ function AppBar() {
   const bar = useAppBar();
   return (
     <header class="sticky top-0 z-30 border-b bg-background/95 backdrop-blur supports-[backdrop-filter]:bg-background/60">
-      <div class="mx-auto flex h-14 w-full max-w-screen-2xl items-center gap-2 px-3 sm:gap-3 sm:px-6">
+      {/*
+        `min-w-0` on the flex container plus `min-w-0` on the wrap-able
+        middle slot lets long content (commit subjects, branch chips) shrink
+        instead of pushing the right cluster off-screen when the viewport
+        is dragged from desktop down to mobile width without a full reload.
+      */}
+      <div class="mx-auto flex h-14 w-full min-w-0 max-w-screen-2xl items-center gap-2 px-3 sm:gap-3 sm:px-6">
         <BrandLink />
         <Show when={bar.back()}>
           {(back) => (
@@ -38,7 +44,7 @@ function AppBar() {
               <TooltipTrigger
                 as={A}
                 href={back().href}
-                class="inline-flex h-9 select-none items-center gap-1.5 rounded-md px-2 text-sm text-muted-foreground transition-colors hover:bg-accent hover:text-foreground"
+                class="inline-flex h-9 shrink-0 select-none items-center gap-1.5 rounded-md px-2 text-sm text-muted-foreground transition-colors hover:bg-accent hover:text-foreground"
                 aria-label={t(back().labelKey)}
               >
                 <BackIcon />
@@ -49,7 +55,10 @@ function AppBar() {
           )}
         </Show>
         <Show when={auth.user()}>
-          <nav class="ml-1 hidden gap-1 text-sm text-muted-foreground md:flex" aria-label="Primary">
+          <nav
+            class="ml-1 hidden min-w-0 gap-1 text-sm text-muted-foreground md:flex"
+            aria-label="Primary"
+          >
             <A
               href="/"
               end
@@ -67,7 +76,7 @@ function AppBar() {
             </A>
           </nav>
         </Show>
-        <div class="ml-auto flex items-center gap-1 sm:gap-2">
+        <div class="ml-auto flex shrink-0 items-center gap-1 sm:gap-2">
           <Show when={bar.filters()}>
             {(f) => (
               <Popover>
@@ -119,19 +128,21 @@ function AppBar() {
 function BrandLink() {
   const t = useT();
   return (
+    // Icon-only brand: the word-mark was pure noise in a viewer that already
+    // has the tab title + favicon. The link itself keeps an `h-9` hit area so
+    // dropping the text didn't reduce the tap target to a 10×10 dot.
     <A
       href="/"
-      class="flex select-none items-center gap-2 font-semibold tracking-tight"
+      class="inline-flex h-9 shrink-0 select-none items-center gap-2 px-1 font-semibold tracking-tight"
       aria-label={t("brand.name")}
     >
       <span aria-hidden="true" class="inline-block h-2.5 w-2.5 shrink-0 rounded-full bg-primary" />
-      <span class="hidden truncate sm:inline">{t("brand.name")}</span>
       <Show when={USE_FAKE_BACKEND}>
         <Tooltip openDelay={250}>
           <TooltipTrigger
             as={Badge}
             variant="warning"
-            class="ml-1 font-mono text-[10px] tracking-wider"
+            class="font-mono text-[10px] tracking-wider"
             title={t("brand.fakeTooltip")}
             aria-label={t("brand.fakeTooltip")}
           >
diff --git a/src/app/app-layout.tsx b/src/app/app-layout.tsx
index 49ceecc..0f2fc58 100644
--- a/src/app/app-layout.tsx
+++ b/src/app/app-layout.tsx
@@ -5,9 +5,17 @@ import { AppBarProvider } from "@/app/app-bar-context";
 function AppLayout(props: ParentProps) {
   return (
     <AppBarProvider>
-      <div class="flex min-h-dvh flex-col">
+      {/*
+        `overflow-x-clip` on the root container kills the brief horizontal
+        scrollbar that appeared when a user resized the window from desktop
+        down to mobile: an inner flex child briefly measures its
+        min-content width before the next reflow shrinks it back. `clip` is
+        preferable to `hidden` here — it doesn't create a new scroll
+        container, so position:sticky on the app bar keeps working.
+      */}
+      <div class="flex min-h-dvh w-full min-w-0 flex-col overflow-x-clip">
         <AppBar />
-        <main class="mx-auto w-full max-w-screen-2xl flex-1 px-3 py-5 sm:px-6 sm:py-8">
+        <main class="mx-auto w-full min-w-0 max-w-screen-2xl flex-1 px-3 py-5 sm:px-6 sm:py-8">
           {props.children}
         </main>
       </div>
diff --git a/src/features/runs/components/run-card.tsx b/src/features/runs/components/run-card.tsx
index 4617584..6c6b7dc 100644
--- a/src/features/runs/components/run-card.tsx
+++ b/src/features/runs/components/run-card.tsx
@@ -75,7 +75,7 @@ function RunCard(props: RunCardProps) {
           <div class="flex min-w-0 flex-wrap items-center gap-1.5 text-xs">
             <For each={props.run.languages.slice(0, LANGUAGES_PREVIEW)}>
               {(lang) => (
-                <span class="rounded bg-muted px-1.5 py-0.5 font-mono uppercase text-muted-foreground">
+                <span class="select-none rounded bg-muted px-1.5 py-0.5 font-mono uppercase text-muted-foreground">
                   {lang}
                 </span>
               )}
diff --git a/src/features/runs/components/run-header.tsx b/src/features/runs/components/run-header.tsx
index 6dcb9bc..fb25020 100644
--- a/src/features/runs/components/run-header.tsx
+++ b/src/features/runs/components/run-header.tsx
@@ -27,7 +27,7 @@ function RunHeader(props: RunHeaderProps) {
             <TooltipTrigger
               as={Badge}
               variant="outline"
-              class="max-w-[14rem] truncate font-mono text-[11px] uppercase tracking-wide"
+              class="max-w-[9rem] truncate font-mono text-[11px] uppercase tracking-wide sm:max-w-[14rem]"
             >
               {props.run.git.branch}
             </TooltipTrigger>
diff --git a/src/features/runs/components/shot-grid.tsx b/src/features/runs/components/shot-grid.tsx
index 9417227..240fcd9 100644
--- a/src/features/runs/components/shot-grid.tsx
+++ b/src/features/runs/components/shot-grid.tsx
@@ -119,7 +119,7 @@ function ShotTile(props: ShotTileProps) {
     <button
       type="button"
       onClick={props.onClick}
-      class="group relative flex aspect-[9/16] select-none overflow-hidden rounded-md border bg-muted/40 text-left ring-offset-background transition will-change-transform focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2"
+      class="group relative flex aspect-[9/16] select-none overflow-hidden rounded-md bg-muted/40 text-left shadow-sm ring-1 ring-black/[0.04] ring-offset-background transition will-change-transform hover:shadow-md focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 dark:ring-white/[0.06]"
       aria-label={`${props.shot.caseId} · ${props.shot.languageCode} · ${props.shot.layoutId}`}
     >
       <Show
diff --git a/src/pages/run.tsx b/src/pages/run.tsx
index d340565..510eaba 100644
--- a/src/pages/run.tsx
+++ b/src/pages/run.tsx
@@ -56,7 +56,7 @@ function RunPage() {
   const flatShots = createMemo(() => store.groups().flatMap((g) => g.shots));
 
   return (
-    <div class="grid gap-5">
+    <div class="grid min-w-0 grid-cols-1 gap-5">
       <Show when={!store.state().loading} fallback={<HeaderSkeleton />}>
         <Show
           when={store.state().run}
diff --git a/src/shared/api/firebase.ts b/src/shared/api/firebase.ts
index 61a6ff9..d3938c0 100644
--- a/src/shared/api/firebase.ts
+++ b/src/shared/api/firebase.ts
@@ -1,10 +1,17 @@
 // Firebase initialization. Web SDK config comes from build-time Vite env;
 // these values are public identifiers (security lives in firestore.rules and
 // storage.rules), so it's fine for them to land in the JS bundle.
+//
+// Firestore uses an explicit memory-only cache. IndexedDB persistence is a
+// foot-gun for a PWA: stale docs would survive sign-out and bleed across
+// users on a shared machine, and the IDB layer occasionally holds a write
+// lock that keeps a freshly-deployed shell stuck reading old data after
+// the service worker has already updated. Memory cache is rebuilt on every
+// page load — predictable, ACL-safe, and small enough for our workload.
 
 import { type FirebaseApp, initializeApp } from "firebase/app";
 import { type Auth, getAuth } from "firebase/auth";
-import { type Firestore, getFirestore } from "firebase/firestore";
+import { type Firestore, initializeFirestore, memoryLocalCache } from "firebase/firestore";
 import { type FirebaseStorage, getStorage } from "firebase/storage";
 
 function readConfig() {
@@ -44,7 +51,11 @@ export function firebaseAuth(): Auth {
 }
 
 export function firestore(): Firestore {
-  if (!_firestore) _firestore = getFirestore(firebaseApp());
+  if (!_firestore) {
+    _firestore = initializeFirestore(firebaseApp(), {
+      localCache: memoryLocalCache(),
+    });
+  }
   return _firestore;
 }
 
diff --git a/src/shared/ui/badge.tsx b/src/shared/ui/badge.tsx
index c5bded6..8245a2b 100644
--- a/src/shared/ui/badge.tsx
+++ b/src/shared/ui/badge.tsx
@@ -4,6 +4,10 @@ import { splitProps } from "solid-js";
 import { cn } from "@/shared/lib/cn";
 
 const badgeVariants = cva(
+  // Note: Badge stays selectable by default. Callers select+copy branch
+  // names, PR numbers, and commit SHAs that are rendered through Badge —
+  // baking `select-none` in would silently break that. Decorative chips
+  // (e.g. language pills on run cards) opt OUT per-call via `class`.
   "inline-flex items-center rounded-full border px-2.5 py-0.5 text-xs font-semibold transition-colors focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2",
   {
     variants: {
diff --git a/src/shared/ui/card.tsx b/src/shared/ui/card.tsx
index f76cac3..ac1a3a5 100644
--- a/src/shared/ui/card.tsx
+++ b/src/shared/ui/card.tsx
@@ -15,9 +15,12 @@ function Card(props: CardProps) {
     <div
       use:ripple={local.interactive || undefined}
       class={cn(
-        "rounded-lg border bg-card text-card-foreground shadow-sm",
+        // Borderless: rely on a soft elevation that lifts slightly on hover
+        // for interactive cards. Subtle ring stays only in dark mode to keep
+        // the card boundary readable against an almost-equal background.
+        "rounded-xl bg-card text-card-foreground shadow-sm ring-1 ring-black/[0.04] dark:ring-white/[0.06]",
         local.interactive &&
-          "cursor-pointer transition duration-150 hover:bg-accent/50 active:scale-[0.99]",
+          "cursor-pointer transition-[transform,box-shadow,background-color] duration-150 hover:bg-accent/40 hover:shadow-md active:scale-[0.99]",
         local.class,
       )}
       {...rest}
diff --git a/src/shared/ui/dropdown-menu.tsx b/src/shared/ui/dropdown-menu.tsx
index de23f2e..e3e4ecb 100644
--- a/src/shared/ui/dropdown-menu.tsx
+++ b/src/shared/ui/dropdown-menu.tsx
@@ -117,15 +117,23 @@ function DropdownMenuRadioItem(props: ComponentProps<typeof KMenu.RadioItem> & {
   );
 }
 
+/**
+ * Free-standing menu label (account header in the avatar dropdown, etc.).
+ * Kobalte's `Menu.GroupLabel` throws "useMenuGroupContext must be used within
+ * a Menu.Group" when rendered outside a group, so wrap it ourselves. Callers
+ * stay decoupled from that detail and just write `<DropdownMenuLabel>`.
+ */
 function DropdownMenuLabel(props: ParentProps<{ class?: string; inset?: boolean }>) {
   const [local, rest] = splitProps(props, ["class", "inset", "children"]);
   return (
-    <KMenu.GroupLabel
-      class={cn("px-2 py-1.5 text-sm font-semibold", local.inset && "pl-8", local.class)}
-      {...rest}
-    >
-      {local.children}
-    </KMenu.GroupLabel>
+    <KMenu.Group>
+      <KMenu.GroupLabel
+        class={cn("px-2 py-1.5 text-sm font-semibold", local.inset && "pl-8", local.class)}
+        {...rest}
+      >
+        {local.children}
+      </KMenu.GroupLabel>
+    </KMenu.Group>
   );
 }
 
diff --git a/vite.config.ts b/vite.config.ts
index 6043ad0..fcc6c97 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -32,11 +32,45 @@ export default defineConfig({
         // The browser's HTTP cache (Cloud Storage already sets immutable
         // Cache-Control on these objects) gives us fast repeat reads inside
         // a session without persisting auth-restricted content past it.
-        globPatterns: ["**/*.{js,css,html,svg,ico,woff,woff2}"],
+        //
+        // *.html is deliberately NOT precached: index.html is the entry
+        // every navigation hits, and precaching it would serve a stale
+        // shell after a deploy until the next SW activation completes.
+        // The NetworkFirst handler below always tries the network for HTML
+        // so a fresh deploy lands on the very next navigation, and falls
+        // back to its own runtime cache when offline.
+        globPatterns: ["**/*.{js,css,svg,ico,woff,woff2}"],
         cleanupOutdatedCaches: true,
-        navigateFallback: "/index.html",
-        // Don't intercept Firebase Auth handler URLs.
-        navigateFallbackDenylist: [/^\/__\/auth\//],
+        // Take over open tabs immediately on activation. Combined with the
+        // NetworkFirst HTML handler this means a deploy lands on the next
+        // navigation without an explicit "update available" prompt.
+        skipWaiting: true,
+        clientsClaim: true,
+        // Explicitly disable workbox's auto-injected NavigationRoute.
+        // vite-plugin-pwa defaults `navigateFallback` to "index.html",
+        // which makes workbox-build emit
+        //   registerRoute(new NavigationRoute(createHandlerBoundToURL("index.html")))
+        // BEFORE our runtime handler. That route would (a) throw at install
+        // time because we no longer precache *.html, and (b) match every
+        // navigation first, preventing the NetworkFirst handler below from
+        // ever firing. Setting to `undefined` overrides the plugin default.
+        navigateFallback: undefined,
+        runtimeCaching: [
+          {
+            // Firebase Auth's signInWithRedirect lands on /__/auth/...
+            // The SW must not intercept that — the redirect handler
+            // expects to hit the network. Anything else that navigates
+            // (a.k.a. clicks a link / types a URL) gets NetworkFirst.
+            urlPattern: ({ request, url }) =>
+              request.mode === "navigate" && !url.pathname.startsWith("/__/auth/"),
+            handler: "NetworkFirst",
+            options: {
+              cacheName: "app-shell",
+              networkTimeoutSeconds: 3,
+              expiration: { maxEntries: 4, maxAgeSeconds: 60 * 60 * 24 * 7 },
+            },
+          },
+        ],
       },
     }),
   ],