diff --git a/CHANGELOG.md b/CHANGELOG.md
index c83c2158..0aca797a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,10 +5,20 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased]
+## [1.2.0] - 2026-03-15
 
 ### Added
 
+#### Mobile Responsive & PWA
+
+- **Mobile-first responsive design**: Full mobile adaptation for the beach scene, overlay panels, and all feature pages
+- **Responsive sprite positioning**: `SpriteData` interface extended with `mobile` and `landscape` override fields; `spriteStyle()` and `labelStyle()` functions select the correct tier (landscape > mobile > desktop)
+- **Landscape orientation support**: Separate sprite positioning config for landscape mode via `useIsMobile` composable returning `isMobile`, `isSmall`, and `isLandscape` reactive refs
+- **Portrait scroll range**: Increased horizontal parallax scroll distance on portrait mobile (`maxOffset` multiplier 1.5x vs 1.2x desktop)
+- **PWA service worker**: Service worker registration for offline caching, gated behind `import.meta.env.PROD` to prevent stale-cache issues during development
+- **Touch gesture support**: `touch-action: pan-x` on `.scene` element enables horizontal swipe navigation on mobile
+- **Dynamic viewport units**: `dvh`/`vh` fallback pattern across all mobile and landscape media queries for correct viewport height on mobile browsers with dynamic toolbars
+
 #### Navigation & Scene Interaction
 
 - **Collapsible NavBar**: Glassmorphism floating navigation menu in the top-right corner; collapsed by default, expands on click with frosted glass styling and monochrome outline icons
@@ -26,8 +36,18 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- **dvh/vh fallback order**: Corrected dynamic viewport height fallback across `mobile.css`, `OverlayPanel.vue`, and `RoleSelectPanel.vue` — `vh` first (fallback), `dvh` second (override)
+- **touch-action scope**: Moved `touch-action: pan-x` from `body` to `.scene` only, so overlay panel content can scroll vertically
+- **Event listener leaks**: Extracted anonymous `resize` and `orientationchange` handlers to named functions with proper cleanup in `onUnmounted` (`useParallax.ts`)
+- **useIsMobile layout flash**: Compute initial `isMobile`/`isSmall`/`isLandscape` values synchronously in `setup()` to prevent false → true flicker on first render
+- **useIsMobile MediaQueryList reuse**: `update()` reads `.matches` from stored MQL objects instead of recreating them on each call
 - **Go static analysis**: Replaced `fmt.Errorf` with `errors.New` for constant error strings across `photo.go`, `task.go`, and `whisper.go` (12 occurrences, SA1006)
 
+### Security
+
+- **Dockerfile hardening**: Replaced `COPY . .` with explicit file/directory copies in both `frontend/Dockerfile` and `backend/Dockerfile` to prevent leaking secrets, `.env` files, or unintended files into container images
+- **Go version alignment**: Updated `backend/Dockerfile` from `golang:1.23-alpine` to `golang:1.25-alpine` to match `go.mod` requirement
+
 ### Performance
 
 - **Gesture control optimization**: Reduced GPU contention on Mac by switching to MediaPipe lite model, lowering camera resolution to 320×240, throttling inference to ~10fps with manual rAF loop, and adding GSAP camera follow throttle with `overwrite: true`
diff --git a/README.md b/README.md
index a3273abe..ebe4360d 100644
--- a/README.md
+++ b/README.md
@@ -25,6 +25,7 @@ AI-powered wellness platform combining emotional companionship, community suppor
 | **Photo Gallery**   | Photo wall with AI-generated images, lifecycle management, and drag/zoom UI        |
 | **Whisper**         | Audio-to-text conversation using speech recognition                                |
 | **Tasks**           | Goal-setting and task-tracking system with partner support                         |
+| **Mobile & PWA**    | Responsive mobile layout with portrait/landscape sprite configs, touch gestures, dynamic viewport units, and offline-capable service worker |
 | **Admin Panel**     | Embedded single-page admin at `/admin` — dashboard, user CRUD, config management   |
 
 ## Quick Start
@@ -55,7 +56,7 @@ MomShell/
 ├── frontend/           # Vue 3 (Vite + TypeScript + Pinia)
 │   └── src/
 │       ├── components/ # Overlay panels + beach scene + React 3D shell
-│       ├── composables/# Animation, parallax, waves, music
+│       ├── composables/# Animation, parallax, waves, music, mobile detection
 │       ├── lib/api/    # API client modules (chat, community, echo, photo, etc.)
 │       ├── stores/     # Pinia stores (auth, UI)
 │       ├── types/      # TypeScript type definitions
diff --git a/backend/Dockerfile b/backend/Dockerfile
index 4f2adb12..760a9281 100644
--- a/backend/Dockerfile
+++ b/backend/Dockerfile
@@ -1,8 +1,10 @@
-FROM golang:1.23-alpine AS builder
+FROM golang:1.25-alpine AS builder
 WORKDIR /app
 COPY go.mod go.sum ./
 RUN go mod download
-COPY . .
+COPY cmd/ cmd/
+COPY internal/ internal/
+COPY pkg/ pkg/
 RUN CGO_ENABLED=0 go build -o /server cmd/server/main.go
 
 FROM alpine:3.20
diff --git a/frontend/Dockerfile b/frontend/Dockerfile
index f7312109..4a77882f 100644
--- a/frontend/Dockerfile
+++ b/frontend/Dockerfile
@@ -2,7 +2,9 @@ FROM node:24-alpine AS builder
 WORKDIR /app
 COPY package.json package-lock.json ./
 RUN npm ci --ignore-scripts
-COPY . .
+COPY index.html tsconfig.json tsconfig.node.json vite.config.ts env.d.ts eslint.config.js ./
+COPY src/ src/
+COPY public/ public/
 ARG VITE_API_BASE_URL=
 ENV VITE_API_BASE_URL=$VITE_API_BASE_URL
 RUN npm run build
diff --git a/frontend/src/composables/useIsMobile.ts b/frontend/src/composables/useIsMobile.ts
index 61dfedfa..df14a089 100644
--- a/frontend/src/composables/useIsMobile.ts
+++ b/frontend/src/composables/useIsMobile.ts
@@ -1,28 +1,36 @@
 import { ref, onMounted, onUnmounted } from "vue";
 
+const MQ_MOBILE = "(max-width: 768px)";
+const MQ_SMALL = "(max-width: 480px)";
+const MQ_LANDSCAPE = "(max-height: 500px) and (orientation: landscape)";
+
 export function useIsMobile() {
-  const isMobile = ref(false);
-  const isSmall = ref(false);
-  const isLandscape = ref(false);
+  const isMobile = ref(
+    typeof window !== "undefined" && window.matchMedia(MQ_MOBILE).matches,
+  );
+  const isSmall = ref(
+    typeof window !== "undefined" && window.matchMedia(MQ_SMALL).matches,
+  );
+  const isLandscape = ref(
+    typeof window !== "undefined" && window.matchMedia(MQ_LANDSCAPE).matches,
+  );
 
   function update() {
-    isMobile.value = window.matchMedia("(max-width: 768px)").matches;
-    isSmall.value = window.matchMedia("(max-width: 480px)").matches;
-    isLandscape.value = window.matchMedia(
-      "(max-height: 500px) and (orientation: landscape)",
-    ).matches;
+    if (mql768 && mql480 && mqlLandscape) {
+      isMobile.value = mql768.matches;
+      isSmall.value = mql480.matches;
+      isLandscape.value = mqlLandscape.matches;
+    }
   }
 
-  let mql768: MediaQueryList;
-  let mql480: MediaQueryList;
-  let mqlLandscape: MediaQueryList;
+  let mql768: MediaQueryList | undefined;
+  let mql480: MediaQueryList | undefined;
+  let mqlLandscape: MediaQueryList | undefined;
 
   onMounted(() => {
-    mql768 = window.matchMedia("(max-width: 768px)");
-    mql480 = window.matchMedia("(max-width: 480px)");
-    mqlLandscape = window.matchMedia(
-      "(max-height: 500px) and (orientation: landscape)",
-    );
+    mql768 = window.matchMedia(MQ_MOBILE);
+    mql480 = window.matchMedia(MQ_SMALL);
+    mqlLandscape = window.matchMedia(MQ_LANDSCAPE);
     update();
     mql768.addEventListener("change", update);
     mql480.addEventListener("change", update);