diff --git a/src/App.css b/src/App.css
index 53aa32e..b2defa1 100644
--- a/src/App.css
+++ b/src/App.css
@@ -5,4 +5,21 @@
   justify-content: center;
   background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
   padding: 20px;
+  box-sizing: border-box;
+  width: 100%;
+}
+
+@media (max-width: 768px) {
+  .app {
+    padding: 15px;
+    align-items: flex-start;
+    padding-top: 20px;
+  }
+}
+
+@media (max-width: 480px) {
+  .app {
+    padding: 10px;
+    padding-top: 15px;
+  }
 }
diff --git a/src/FlappyBird.css b/src/FlappyBird.css
index 1f763a5..9e4b7b5 100644
--- a/src/FlappyBird.css
+++ b/src/FlappyBird.css
@@ -4,6 +4,11 @@
   padding: 20px;
   text-align: center;
   font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', sans-serif;
+  width: 100%;
+  box-sizing: border-box;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
 }
 
 .flappy-bird-container h1 {
@@ -15,19 +20,25 @@
 
 .game-area {
   position: relative;
-  display: inline-block;
-  margin-bottom: 20px;
+  display: block;
+  margin: 0 auto 20px auto;
   border-radius: 10px;
   box-shadow: 0 8px 32px rgba(0,0,0,0.2);
   overflow: hidden;
+  width: 100%;
+  max-width: 800px;
 }
 
 .game-canvas {
   display: block;
+  margin: 0 auto;
   border: 3px solid #34495e;
   border-radius: 10px;
   cursor: pointer;
   background: linear-gradient(to bottom, #87CEEB 0%, #98FB98 100%);
+  width: 100%;
+  height: auto;
+  aspect-ratio: 2 / 1;
 }
 
 .game-canvas:hover {
@@ -106,17 +117,24 @@
 /* Responsive design */
 @media (max-width: 850px) {
   .flappy-bird-container {
-    padding: 10px;
+    padding: 15px;
+    max-width: 100%;
+  }
+  
+  .game-area {
+    width: 100%;
+    margin-bottom: 15px;
   }
   
   .game-canvas {
     width: 100%;
-    max-width: 800px;
-    height: auto;
+    max-width: 100%;
+    border-width: 2px;
   }
   
   .flappy-bird-container h1 {
     font-size: 2rem;
+    margin-bottom: 15px;
   }
   
   .scores {
@@ -124,7 +142,7 @@
   }
   
   .game-message {
-    max-width: 250px;
+    max-width: 280px;
     padding: 15px 20px;
   }
   
@@ -135,11 +153,28 @@
   .game-message.game-over p:first-child {
     font-size: 20px;
   }
+  
+  .instructions {
+    margin-top: 15px;
+  }
 }
 
 @media (max-width: 480px) {
+  .flappy-bird-container {
+    padding: 10px;
+  }
+  
   .flappy-bird-container h1 {
     font-size: 1.5rem;
+    margin-bottom: 10px;
+  }
+  
+  .game-area {
+    margin-bottom: 10px;
+  }
+  
+  .game-canvas {
+    border-width: 2px;
   }
   
   .scores {
@@ -148,11 +183,50 @@
     font-size: 12px;
   }
   
+  .game-message {
+    max-width: 240px;
+    padding: 12px 15px;
+  }
+  
+  .game-message p {
+    font-size: 13px;
+    margin: 6px 0;
+  }
+  
+  .game-message.game-over p:first-child {
+    font-size: 18px;
+  }
+  
   .instructions {
-    padding: 15px;
+    padding: 12px;
+    margin-top: 10px;
   }
   
   .instructions p {
-    font-size: 14px;
+    font-size: 13px;
+    margin: 8px 0;
+  }
+}
+
+@media (max-width: 320px) {
+  .flappy-bird-container {
+    padding: 8px;
+  }
+  
+  .flappy-bird-container h1 {
+    font-size: 1.3rem;
+  }
+  
+  .game-message {
+    max-width: 200px;
+    padding: 10px 12px;
+  }
+  
+  .instructions {
+    padding: 10px;
+  }
+  
+  .instructions p {
+    font-size: 12px;
   }
 }
\ No newline at end of file
diff --git a/src/FlappyBird.jsx b/src/FlappyBird.jsx
index f36bd33..2fc7a7e 100644
--- a/src/FlappyBird.jsx
+++ b/src/FlappyBird.jsx
@@ -39,6 +39,26 @@ function FlappyBird() {
     frameCount: 0
   })
 
+  // Update canvas size to maintain aspect ratio
+  const updateCanvasSize = useCallback(() => {
+    const canvas = canvasRef.current
+    if (!canvas) return
+
+    const container = canvas.parentElement
+    const containerWidth = container.clientWidth
+    const aspectRatio = GAME_CONFIG.CANVAS_WIDTH / GAME_CONFIG.CANVAS_HEIGHT
+    
+    let canvasWidth = Math.min(containerWidth - 20, GAME_CONFIG.CANVAS_WIDTH)
+    let canvasHeight = canvasWidth / aspectRatio
+
+    canvas.style.width = `${canvasWidth}px`
+    canvas.style.height = `${canvasHeight}px`
+    
+    // Set internal resolution
+    canvas.width = GAME_CONFIG.CANVAS_WIDTH
+    canvas.height = GAME_CONFIG.CANVAS_HEIGHT
+  }, [])
+
   const jump = useCallback(() => {
     if (gameState === GAME_STATES.START) {
       setGameState(GAME_STATES.PLAYING)
@@ -167,6 +187,17 @@ function FlappyBird() {
     gameLoopRef.current = requestAnimationFrame(gameLoop)
   }, [gameState, score, highScore, checkCollision])
 
+  useEffect(() => {
+    updateCanvasSize()
+    
+    const handleResize = () => {
+      updateCanvasSize()
+    }
+    
+    window.addEventListener('resize', handleResize)
+    return () => window.removeEventListener('resize', handleResize)
+  }, [updateCanvasSize])
+
   useEffect(() => {
     gameLoopRef.current = requestAnimationFrame(gameLoop)
     return () => {