/**** 
* Plugins
****/ 
var tween = LK.import("@upit/tween.v1");
var storage = LK.import("@upit/storage.v1", {
	unlockedBirds: [1],
	totalCoins: 0
});

/**** 
* Classes
****/ 
var Bird = Container.expand(function () {
	var self = Container.call(this);
	var birdGraphics = self.attachAsset('bird', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.velocityY = 0;
	self.gravity = 0.6;
	self.flapPower = -12;
	self.isAlive = true;
	self.flap = function () {
		self.velocityY = self.flapPower;
		LK.getSound('flap').play();
	};
	self.update = function () {
		if (!self.isAlive) return;
		self.velocityY += self.gravity;
		self.lastY = self.y;
		self.y += self.velocityY;
		if (self.lastY - 25 >= 0 && self.y - 25 < 0) {
			self.isAlive = false;
			LK.showGameOver();
		}
		if (self.y - 25 < 0) {
			self.y = 25;
			self.velocityY = 0;
		}
	};
	return self;
});
var BirdSelector = Container.expand(function () {
	var self = Container.call(this);
	self.birdId = 0;
	self.isUnlocked = false;
	self.isSelected = false;
	var selectorGraphics = self.attachAsset('bird', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	selectorGraphics.width = 80;
	selectorGraphics.height = 67;
	var lockText = new Text2('LOCKED', {
		size: 40,
		fill: 0xFF0000
	});
	lockText.anchor.set(0.5, 0.5);
	lockText.visible = false;
	self.addChild(lockText);
	self.setLocked = function (locked) {
		self.isUnlocked = !locked;
		lockText.visible = locked;
		selectorGraphics.alpha = locked ? 0.3 : 1;
	};
	return self;
});
var Coin = Container.expand(function () {
	var self = Container.call(this);
	var coinGraphics = self.attachAsset('coin', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = -6;
	self.isCollected = false;
	self.update = function () {
		self.x += self.speed;
	};
	return self;
});
var Ground = Container.expand(function () {
	var self = Container.call(this);
	var groundGraphics = self.attachAsset('ground', {
		anchorX: 0,
		anchorY: 0
	});
	self.x = 0;
	self.y = 2582;
	return self;
});
var Pipe = Container.expand(function () {
	var self = Container.call(this);
	self.speed = -6;
	self.gapSize = 250;
	self.hasBeenScored = false;
	var topPipe = self.attachAsset('pipe', {
		anchorX: 0.5,
		anchorY: 1
	});
	var bottomPipe = self.attachAsset('pipe', {
		anchorX: 0.5,
		anchorY: 0
	});
	self.setup = function (gapY) {
		self.gapY = gapY;
		topPipe.y = gapY - self.gapSize / 2;
		bottomPipe.y = gapY + self.gapSize / 2;
		topPipe.x = 50;
		bottomPipe.x = 50;
	};
	self.update = function () {
		self.x += self.speed;
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x87CEEB
});

/**** 
* Game Code
****/ 
var skyGradient = new Container();
game.addChild(skyGradient);
var topSky = LK.getAsset('skyTop', {
	anchorX: 0,
	anchorY: 0,
	x: 0,
	y: 0
});
skyGradient.addChild(topSky);
var bottomSky = LK.getAsset('skyBottom', {
	anchorX: 0,
	anchorY: 0,
	x: 0,
	y: 1366
});
skyGradient.addChild(bottomSky);
var gameStarted = false;
var gamePaused = false;
var menuContainer = new Container();
game.addChild(menuContainer);
var titleTxt = new Text2('FLAPPY BIRD', {
	size: 200,
	fill: 0xFFFFFF
});
titleTxt.anchor.set(0.5, 0.5);
titleTxt.x = 1024;
titleTxt.y = 600;
menuContainer.addChild(titleTxt);
var instructionsTxt = new Text2('TAP TO FLAP', {
	size: 120,
	fill: 0xFFFFFF
});
instructionsTxt.anchor.set(0.5, 0.5);
instructionsTxt.x = 1024;
instructionsTxt.y = 1100;
menuContainer.addChild(instructionsTxt);
var birdSelectionTxt = new Text2('SELECT BIRD', {
	size: 100,
	fill: 0xFFFFFF
});
birdSelectionTxt.anchor.set(0.5, 0.5);
birdSelectionTxt.x = 1024;
birdSelectionTxt.y = 1250;
menuContainer.addChild(birdSelectionTxt);
var birdSelectorsContainer = new Container();
menuContainer.addChild(birdSelectorsContainer);
var unlockedBirds = storage.unlockedBirds || [1];
var totalCoinsCollected = storage.totalCoins || 0;
var birdSelectors = [];
for (var b = 1; b <= 5; b++) {
	var birdSelector = new BirdSelector();
	birdSelectorsContainer.addChild(birdSelector);
	birdSelector.birdId = b;
	birdSelector.x = 300 + (b - 1) * 350;
	birdSelector.y = 1350;
	var coinsNeeded = (b - 1) * 50;
	var isBirdUnlocked = false;
	for (var ub = 0; ub < unlockedBirds.length; ub++) {
		if (unlockedBirds[ub] === b) {
			isBirdUnlocked = true;
			break;
		}
	}
	birdSelector.setLocked(!isBirdUnlocked);
	if (b === 1) {
		birdSelector.isSelected = true;
	}
	var costTxt = new Text2(coinsNeeded + ' coins', {
		size: 30,
		fill: 0xFFFFFF
	});
	costTxt.anchor.set(0.5, 0.5);
	costTxt.y = 50;
	birdSelector.addChild(costTxt);
	birdSelectors.push(birdSelector);
}
var levelSelectionTxt = new Text2('SELECT LEVEL', {
	size: 100,
	fill: 0xFFFFFF
});
levelSelectionTxt.anchor.set(0.5, 0.5);
levelSelectionTxt.x = 1024;
levelSelectionTxt.y = 1500;
menuContainer.addChild(levelSelectionTxt);
var levelButtonsContainer = new Container();
menuContainer.addChild(levelButtonsContainer);
var levelButtons = [];
for (var l = 1; l <= 5; l++) {
	var levelBtn = new Container();
	levelButtonsContainer.addChild(levelBtn);
	var btnGraphics = levelBtn.attachAsset('pipe', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	btnGraphics.width = 150;
	btnGraphics.height = 120;
	btnGraphics.tint = 0x3498db;
	levelBtn.x = 300 + (l - 1) * 350;
	levelBtn.y = 1600;
	levelBtn.levelNumber = l;
	levelBtn.isSelected = l === 1;
	var btnTxt = new Text2(String(l), {
		size: 80,
		fill: 0xFFFFFF
	});
	btnTxt.anchor.set(0.5, 0.5);
	levelBtn.addChild(btnTxt);
	levelButtons.push(levelBtn);
}
var tapToStartTxt = new Text2('TAP TO START', {
	size: 100,
	fill: 0xFFD700
});
tapToStartTxt.anchor.set(0.5, 0.5);
tapToStartTxt.x = 1024;
tapToStartTxt.y = 1750;
menuContainer.addChild(tapToStartTxt);
var bird = game.addChild(new Bird());
bird.x = 300;
bird.y = 1366;
bird.lastY = bird.y;
bird.lastWasCollidingWithPipe = false;
bird.visible = false;
var ground = game.addChild(new Ground());
ground.visible = false;
var pipes = [];
var coins = [];
var pipeSpawnTimer = 0;
var pipeSpawnInterval = 200;
var nextGapPosition = 0;
var currentLevel = 1;
var pipsPassedInLevel = 0;
var pipsRequiredToLevelUp = 5;
var coinsCollected = 0;
var scoreTxt = new Text2('Score: 0', {
	size: 120,
	fill: 0xFFFFFF
});
scoreTxt.anchor.set(0.5, 0);
scoreTxt.y = 20;
LK.gui.top.addChild(scoreTxt);
scoreTxt.visible = false;
var coinsTxt = new Text2('Total Coins: 0', {
	size: 80,
	fill: 0xFFD700
});
coinsTxt.anchor.set(0.5, 0);
coinsTxt.y = 150;
LK.gui.top.addChild(coinsTxt);
coinsTxt.visible = false;
var gameScore = 0;
var levelTxt = new Text2('Level 1', {
	size: 100,
	fill: 0xFFFFFF
});
levelTxt.anchor.set(0.5, 0);
levelTxt.y = 150;
LK.gui.top.addChild(levelTxt);
levelTxt.visible = false;
function spawnPipe() {
	var minGapY = 400;
	var maxGapY = 1800;
	var randomGapY = minGapY + Math.random() * (maxGapY - minGapY);
	var newPipe = game.addChild(new Pipe());
	newPipe.x = 2048 + 100;
	var basePipeGapSize = newPipe.gapSize;
	newPipe.gapSize = Math.max(120, basePipeGapSize - (currentLevel - 1) * 30);
	newPipe.setup(randomGapY);
	newPipe.lastX = newPipe.x;
	newPipe.hasBeenScored = false;
	pipes.push(newPipe);
	var coinOffset = (Math.random() - 0.5) * 150;
	var newCoin = game.addChild(new Coin());
	newCoin.x = newPipe.x;
	newCoin.y = randomGapY + coinOffset;
	newCoin.lastX = newCoin.x;
	newCoin.isCollected = false;
	coins.push(newCoin);
}
game.down = function (x, y, obj) {
	if (!gameStarted) {
		var clickedBird = false;
		for (var sb = 0; sb < birdSelectors.length; sb++) {
			var selector = birdSelectors[sb];
			var selectorBounds = selector.getBounds();
			if (x >= selectorBounds.x && x <= selectorBounds.x + selectorBounds.width && y >= selectorBounds.y && y <= selectorBounds.y + selectorBounds.height) {
				if (selector.isUnlocked) {
					for (var dbs = 0; dbs < birdSelectors.length; dbs++) {
						birdSelectors[dbs].isSelected = false;
						birdSelectors[dbs].children[1].tint = 0xFFFFFF;
					}
					selector.isSelected = true;
					selector.children[1].tint = 0xFFD700;
					clickedBird = true;
				} else {
					var coinsNeeded = (selector.birdId - 1) * 50;
					if (totalCoinsCollected >= coinsNeeded) {
						var unlockedIndex = unlockedBirds.length;
						unlockedBirds.push(selector.birdId);
						storage.unlockedBirds = unlockedBirds;
						selector.setLocked(false);
						selector.isSelected = true;
						for (var dus = 0; dus < birdSelectors.length; dus++) {
							birdSelectors[dus].children[1].tint = 0xFFFFFF;
						}
						selector.children[1].tint = 0xFFD700;
						clickedBird = true;
					}
				}
				break;
			}
		}
		var clickedLevel = false;
		for (var b = 0; b < levelButtons.length; b++) {
			var btn = levelButtons[b];
			var buttonBounds = btn.getBounds();
			if (x >= buttonBounds.x && x <= buttonBounds.x + buttonBounds.width && y >= buttonBounds.y && y <= buttonBounds.y + buttonBounds.height) {
				for (var c = 0; c < levelButtons.length; c++) {
					levelButtons[c].isSelected = false;
					levelButtons[c].children[0].tint = 0xFFFFFF;
				}
				btn.isSelected = true;
				btn.children[0].tint = 0xFFD700;
				currentLevel = btn.levelNumber;
				clickedLevel = true;
				break;
			}
		}
		if (!clickedBird && !clickedLevel) {
			gameStarted = true;
			gamePaused = false;
			menuContainer.visible = false;
			bird.visible = true;
			ground.visible = true;
			scoreTxt.visible = true;
			levelTxt.visible = true;
			coinsTxt.visible = true;
			levelTxt.setText('Level ' + currentLevel);
			pipsPassedInLevel = 0;
			bird.gravity = 0.6 + (currentLevel - 1) * 0.15;
			bird.flap();
		}
	} else if (bird.isAlive) {
		bird.flap();
	}
};
game.update = function () {
	if (!gameStarted || gamePaused) return;
	bird.update();
	pipeSpawnTimer++;
	var currentSpawnInterval = Math.max(80, pipeSpawnInterval - (currentLevel - 1) * 25);
	if (pipeSpawnTimer >= currentSpawnInterval) {
		spawnPipe();
		pipeSpawnTimer = 0;
	}
	for (var i = coins.length - 1; i >= 0; i--) {
		var coin = coins[i];
		coin.update();
		if (!coin.lastX) coin.lastX = coin.x;
		if (coin.x < -100) {
			coin.destroy();
			coins.splice(i, 1);
		}
		if (bird.isAlive && !coin.isCollected) {
			var coinCollisionDistance = Math.sqrt((bird.x - coin.x) * (bird.x - coin.x) + (bird.y - coin.y) * (bird.y - coin.y));
			if (coinCollisionDistance < 50) {
				coin.isCollected = true;
				coinsCollected++;
				totalCoinsCollected++;
				storage.totalCoins = totalCoinsCollected;
				coinsTxt.setText('Total Coins: ' + totalCoinsCollected);
				LK.getSound('coin').play();
				coin.destroy();
				coins.splice(i, 1);
			}
		}
	}
	for (var i = pipes.length - 1; i >= 0; i--) {
		var pipe = pipes[i];
		pipe.update();
		if (!pipe.lastX) pipe.lastX = pipe.x;
		if (pipe.lastX > 300 && pipe.x <= 300 && !pipe.hasBeenScored) {
			pipe.hasBeenScored = true;
			gameScore++;
			LK.setScore(gameScore);
			pipsPassedInLevel++;
			scoreTxt.setText('Score: ' + gameScore);
			LK.getSound('score').play();
			if (pipsPassedInLevel >= pipsRequiredToLevelUp) {
				currentLevel++;
				pipsPassedInLevel = 0;
				levelTxt.setText('Level ' + currentLevel);
			}
		}
		pipe.lastX = pipe.x;
		if (pipe.x < -150) {
			pipe.destroy();
			pipes.splice(i, 1);
		}
		if (bird.isAlive && bird.lastWasCollidingWithPipe === undefined) {
			bird.lastWasCollidingWithPipe = false;
		}
		if (bird.isAlive) {
			var birdLeft = bird.x - 25;
			var birdRight = bird.x + 25;
			var birdTop = bird.y - 25;
			var birdBottom = bird.y + 25;
			var pipeLeft = pipe.x - 50;
			var pipeRight = pipe.x + 50;
			var isCollidingNow = false;
			if (birdRight > pipeLeft && birdLeft < pipeRight) {
				if (birdTop < pipe.gapY - pipe.gapSize / 2 || birdBottom > pipe.gapY + pipe.gapSize / 2) {
					isCollidingNow = true;
				}
			}
			if (!bird.lastWasCollidingWithPipe && isCollidingNow) {
				bird.isAlive = false;
				LK.showGameOver();
			}
			bird.lastWasCollidingWithPipe = isCollidingNow;
		}
	}
};
LK.playMusic('bgmusic', {
	loop: true
});

===================================================================
--- original.js
+++ change.js
@@ -123,8 +123,24 @@
 
 /**** 
 * Game Code
 ****/ 
+var skyGradient = new Container();
+game.addChild(skyGradient);
+var topSky = LK.getAsset('skyTop', {
+	anchorX: 0,
+	anchorY: 0,
+	x: 0,
+	y: 0
+});
+skyGradient.addChild(topSky);
+var bottomSky = LK.getAsset('skyBottom', {
+	anchorX: 0,
+	anchorY: 0,
+	x: 0,
+	y: 1366
+});
+skyGradient.addChild(bottomSky);
 var gameStarted = false;
 var gamePaused = false;
 var menuContainer = new Container();
 game.addChild(menuContainer);