Improve: <!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <meta
    name="viewport"
    content="width=device-width, initial-scale=1, user-scalable=no, viewport-fit=cover"
  />
  <title>Cyber‑Neon Snake</title>
  <style>
    /* Reset & Base */
    *, *::before, *::after {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    html, body {
      height: 100%;
      overflow: hidden;
      user-select: none;
      background: linear-gradient(45deg, #0f2027, #203a43, #2c5364);
      background-size: 600% 600%;
      animation: bgShift 20s ease infinite;
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      color: #0f9;
      touch-action: manipulation;
    }
    @keyframes bgShift {
      0% { background-position: 0% 50%; }
      50% { background-position: 100% 50%; }
      100% { background-position: 0% 50%; }
    }

    /* Game Frame */
    #game {
      position: relative;
      width: 90vmin;
      height: 90vmin;
      background: #111;
      border: 4px solid #0f9;
      border-radius: 20px;
      box-shadow: inset 0 0 20px #0f9a, 0 0 30px rgba(0, 255, 153, 0.2);
      touch-action: none;
      user-select: none;
      outline: none;
      overflow: hidden;
    }
    canvas {
      width: 100%;
      height: 100%;
      display: block;
      background: #111;
      border-radius: 20px;
    }

    /* Neon Scoreboard */
    @keyframes neonFlicker {
      0%, 18%, 22%, 25%, 53%, 57%, 100% {
        text-shadow:
          0 0 5px #0f9,
          0 0 10px #0f9,
          0 0 20px #0f9,
          0 0 40px #0ff,
          0 0 80px #0ff;
      }
      20%, 24%, 55% {
        text-shadow: none;
      }
    }
    #scoreboard {
      margin-top: 12px;
      text-align: center;
      font-size: 1.5rem;
      font-weight: 700;
      animation: neonFlicker 3s infinite;
      user-select: none;
      display: flex;
      justify-content: center;
      gap: 20px;
      flex-wrap: wrap;
    }
    #scoreboard.flash {
      color: #fff;
      text-shadow:
        0 0 25px #0ff,
        0 0 50px #0ff,
        0 0 75px #0ff;
      transition: text-shadow 0.2s, color 0.2s;
    }
    .score-container {
      display: flex;
      flex-direction: column;
      align-items: center;
      min-width: 120px;
      background: rgba(0, 20, 15, 0.7);
      padding: 8px 16px;
      border-radius: 12px;
      border: 1px solid #0f9;
      box-shadow: 0 0 10px rgba(0, 255, 153, 0.3);
    }
    .score-label {
      font-size: 0.9rem;
      opacity: 0.8;
      margin-bottom: 4px;
    }

    /* Controls */
    #controls {
      margin-top: 12px;
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 12px;
      width: 90vmin;
      max-width: 400px;
    }
    .btn {
      background: #0f9;
      border: none;
      border-radius: 12px;
      padding: 14px 0;
      font-size: 1.4rem;
      font-weight: 700;
      box-shadow: 0 0 20px #0f9;
      cursor: pointer;
      transition: background 0.2s, box-shadow 0.2s, transform 0.1s;
      user-select: none;
      color: #000;
      outline-offset: 2px;
      outline-color: transparent;
      outline-style: solid;
    }
    .btn:hover,
    .btn:focus-visible {
      background: #0cffaa;
      box-shadow: 0 0 30px #0cffaa;
      outline-color: #0cffaa;
      transform: scale(1.05);
    }
    .btn:active {
      background: #0c7;
      box-shadow: inset 0 0 30px #0c7;
      transform: scale(0.95);
    }
    @media (max-width: 400px) {
      .btn {
        font-size: 1.2rem;
        padding: 10px 0;
      }
    }

    /* Top Control Bar */
    #top-controls {
      display: flex;
      justify-content: space-between;
      width: 90vmin;
      max-width: 400px;
      margin-bottom: 12px;
      gap: 12px;
    }
    #top-controls .btn {
      flex: 1;
      padding: 10px 0;
      font-size: 1.1rem;
    }
    #difficulty {
      background: #0f9;
      color: #000;
      border: none;
      border-radius: 12px;
      padding: 0 15px;
      font-size: 1.1rem;
      font-weight: 700;
      box-shadow: 0 0 20px #0f9;
      cursor: pointer;
      outline: none;
      text-align: center;
    }
    #difficulty option {
      background: #111;
      color: #0f9;
    }

    /* Game Over Modal */
    #gameOverModal {
      position: fixed;
      top: 0; left: 0; right: 0; bottom: 0;
      background: rgba(0,0,0,0.85);
      display: flex;
      align-items: center;
      justify-content: center;
      color: #0f9;
      font-size: 2rem;
      font-weight: 700;
      text-align: center;
      padding: 1rem;
      z-index: 1000;
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.3s ease;
      border-radius: 12px;
      user-select: none;
      backdrop-filter: blur(5px);
    }
    #gameOverModal.show {
      opacity: 1;
      pointer-events: auto;
    }
    #gameOverModal button {
      margin-top: 1rem;
      background: #0ff;
      border: none;
      border-radius: 12px;
      padding: 12px 24px;
      font-size: 1.3rem;
      font-weight: 700;
      color: #000;
      cursor: pointer;
      box-shadow: 0 0 25px #0ff;
      transition: background 0.3s, box-shadow 0.3s, transform 0.2s;
    }
    #gameOverModal button:hover,
    #gameOverModal button:focus-visible {
      background: #0cc;
      box-shadow: 0 0 40px #0cc;
      outline: none;
      transform: scale(1.05);
    }
    #gameOverModal button:active {
      background: #099;
      box-shadow: inset 0 0 30px #099;
      transform: scale(0.95);
    }
    .modal-content {
      background: rgba(10, 30, 30, 0.95);
      border: 3px solid #0f9;
      border-radius: 20px;
      padding: 2rem;
      max-width: 90%;
      box-shadow: 0 0 50px rgba(0, 255, 153, 0.5);
    }
    .power-up-indicator {
      display: inline-block;
      width: 20px;
      height: 20px;
      border-radius: 50%;
      margin: 0 5px;
      vertical-align: middle;
      box-shadow: 0 0 8px currentColor;
    }

    /* Pause Overlay */
    #pauseOverlay {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(0, 0, 0, 0.7);
      display: flex;
      align-items: center;
      justify-content: center;
      color: #0ff;
      font-size: 3rem;
      font-weight: 700;
      z-index: 500;
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.3s ease;
      border-radius: 20px;
      text-shadow: 0 0 20px #0ff;
      backdrop-filter: blur(3px);
    }
    #pauseOverlay.show {
      opacity: 1;
      pointer-events: auto;
    }

    /* Instructions */
    #instructions {
      margin-top: 15px;
      text-align: center;
      font-size: 0.9rem;
      max-width: 90vmin;
      color: rgba(0, 255, 153, 0.7);
      line-height: 1.5;
    }
    .highlight {
      color: #0ff;
      font-weight: bold;
    }
  </style>
</head>
<body>
  <div id="top-controls">
    <button id="pauseBtn" class="btn" type="button" aria-label="Pause game">⏸️ Pause</button>
    <select id="difficulty" aria-label="Game difficulty">
      <option value="easy">Easy</option>
      <option value="medium" selected>Medium</option>
      <option value="hard">Hard</option>
      <option value="insane">Insane</option>
    </select>
    <button id="restartBtn" class="btn" type="button" aria-label="Restart game">🔄 Restart</button>
  </div>
  
  <main id="game" role="region" aria-label="Snake game area" tabindex="0">
    <canvas id="canvas" aria-live="polite" aria-label="Game canvas"></canvas>
    <div id="pauseOverlay">PAUSED</div>
  </main>

  <div id="scoreboard" aria-live="polite" aria-atomic="true" role="status">
    <div class="score-container">
      <div class="score-label">SCORE</div>
      <div id="currentScore">0</div>
    </div>
    <div class="score-container">
      <div class="score-label">HIGH SCORE</div>
      <div id="highScore">0</div>
    </div>
    <div class="score-container">
      <div class="score-label">SPEED</div>
      <div id="speedDisplay">10</div>
    </div>
  </div>

  <nav id="controls" aria-label="Directional controls">
    <button class="btn" data-dir="left" aria-label="Move left" type="button">←</button>
    <button class="btn" data-dir="up" aria-label="Move up" type="button">↑</button>
    <button class="btn" data-dir="down" aria-label="Move down" type="button">↓</button>
    <button class="btn" data-dir="right" aria-label="Move right" type="button">→</button>
  </nav>

  <div id="instructions">
    <div>Collect <span class="highlight">apples</span> for points. Avoid walls and yourself!</div>
    <div>Power-ups: <span class="power-up-indicator" style="background: gold;"></span> Speed Boost 
      <span class="power-up-indicator" style="background: #ff00ff;"></span> Score Multiplier</div>
  </div>

  <!-- Game Over Modal -->
  <div id="gameOverModal" role="dialog" aria-modal="true" aria-labelledby="gameOverTitle" aria-describedby="gameOverDesc" tabindex="-1">
    <div class="modal-content">
      <h2 id="gameOverTitle">Game Over!</h2>
      <p id="gameOverDesc">Your final score is <span id="finalScore">0</span>.</p>
      <button id="modalRestartBtn" type="button">Restart Game</button>
    </div>
  </div>

  <!-- Sound effects -->
  <audio id="eatSfx" preload="auto" aria-hidden="true"></audio>
  <audio id="powerSfx" preload="auto" aria-hidden="true"></audio>
  <audio id="gameOverSfx" preload="auto" aria-hidden="true"></audio>

  <script>
  (function(){
    'use strict';

    // Generate sound effects dynamically
    function generateEatSound() {
      const context = new (window.AudioContext || window.webkitAudioContext)();
      const oscillator = context.createOscillator();
      const gainNode = context.createGain();
      
      oscillator.type = 'sine';
      oscillator.frequency.setValueAtTime(523.25, context.currentTime); // C5
      oscillator.frequency.exponentialRampToValueAtTime(1046.5, context.currentTime + 0.1); // C6
      
      gainNode.gain.setValueAtTime(0.3, context.currentTime);
      gainNode.gain.exponentialRampToValueAtTime(0.01, context.currentTime + 0.3);
      
      oscillator.connect(gainNode);
      gainNode.connect(context.destination);
      
      oscillator.start();
      oscillator.stop(context.currentTime + 0.3);
    }

    function generatePowerSound() {
      const context = new (window.AudioContext || window.webkitAudioContext)();
      const oscillator = context.createOscillator();
      const gainNode = context.createGain();
      
      oscillator.type = 'sawtooth';
      oscillator.frequency.setValueAtTime(220, context.currentTime); // A3
      oscillator.frequency.exponentialRampToValueAtTime(880, context.currentTime + 0.2); // A5
      
      gainNode.gain.setValueAtTime(0.3, context.currentTime);
      gainNode.gain.exponentialRampToValueAtTime(0.01, context.currentTime + 0.4);
      
      oscillator.connect(gainNode);
      gainNode.connect(context.destination);
      
      oscillator.start();
      oscillator.stop(context.currentTime + 0.4);
    }

    function generateGameOverSound() {
      const context = new (window.AudioContext || window.webkitAudioContext)();
      const oscillator = context.createOscillator();
      const gainNode = context.createGain();
      
      oscillator.type = 'square';
      oscillator.frequency.setValueAtTime(392, context.currentTime); // G4
      oscillator.frequency.exponentialRampToValueAtTime(130.81, context.currentTime + 0.8); // C3
      
      gainNode.gain.setValueAtTime(0.4, context.currentTime);
      gainNode.gain.exponentialRampToValueAtTime(0.01, context.currentTime + 0.8);
      
      oscillator.connect(gainNode);
      gainNode.connect(context.destination);
      
      oscillator.start();
      oscillator.stop(context.currentTime + 0.8);
    }

    // DOM & audio refs
    const game       = document.getElementById('game');
    const canvas     = document.getElementById('canvas');
    const ctx        = canvas.getContext('2d');
    const scoreEl    = document.getElementById('currentScore');
    const highEl     = document.getElementById('highScore');
    const speedEl    = document.getElementById('speedDisplay');
    const sb         = document.getElementById('scoreboard');
    const eatSfx     = document.getElementById('eatSfx');
    const powerSfx   = document.getElementById('powerSfx');
    const gameOverSfx = document.getElementById('gameOverSfx');
    const btns       = document.querySelectorAll('.btn');
    const restartBtn = document.getElementById('restartBtn');
    const pauseBtn   = document.getElementById('pauseBtn');
    const difficulty = document.getElementById('difficulty');
    const gameOverModal = document.getElementById('gameOverModal');
    const pauseOverlay = document.getElementById('pauseOverlay');
    const finalScoreEl = document.getElementById('finalScore');
    const modalRestartBtn = document.getElementById('modalRestartBtn');

    // Pre-rendered grid for performance
    const gridCanvas = document.createElement('canvas');
    const gridCtx = gridCanvas.getContext('2d');

    // Config & state
    const tileCount    = 24;
    let gridSize;
    let fps          = 10;
    const maxApples    = 3;
    let snake, velocity, nextVel, apples, powerUps, score, gameOver, isPaused;
    let comboCounter, lastAppleTime, hue;
    let effects;
    let highScore     = parseInt(localStorage.getItem('snakeHighScore'),10) || 0;
    let snakeTrail = [];
    let powerUpActive = null;
    let powerUpTimer = 0;
    let powerUpDuration = 5000; // 5 seconds
    
    // Timing for fixed FPS using delta accumulator
    let lastTime = 0;
    let delta = 0;
    let interval = 1000 / fps;

    // Power-up types
    const POWERUP_TYPES = {
      SPEED_BOOST: { color: 'gold', effect: () => fps *= 1.5, reverse: () => fps /= 1.5 },
      SCORE_MULTIPLIER: { color: '#ff00ff', effect: () => {}, reverse: () => {} }
    };

    // Initialize or reset game state
    function initGame() {
      snake = [{x:12,y:12}, {x:11,y:12}, {x:10,y:12}];
      velocity = {x:1, y:0};
      nextVel = {x:1, y:0};
      apples = [];
      powerUps = [];
      score = 0;
      comboCounter = 0;
      lastAppleTime = 0;
      hue = 0;
      effects = { score: [], particles: [] };
      gameOver = false;
      isPaused = false;
      powerUpActive = null;
      powerUpTimer = 0;
      snakeTrail = [];
      fps = 10;
      interval = 1000 / fps;
      scoreEl.textContent = score;
      speedEl.textContent = fps;
      pauseOverlay.classList.remove('show');
      gameOverModal.classList.remove('show');
      spawnApples();
      game.focus();
    }

    // Dynamic canvas sizing
    function resizeCanvas(){
      const size = game.clientWidth;
      canvas.width  = size;
      canvas.height = size;
      gridSize      = size / tileCount;
      
      // Pre-render grid to offscreen canvas
      gridCanvas.width = size;
      gridCanvas.height = size;
      gridCtx.strokeStyle = '#222';
      gridCtx.lineWidth = 1;
      for(let i=0; i<=tileCount; i++){
        const pos = i * gridSize;
        gridCtx.beginPath();
        gridCtx.moveTo(pos, 0);
        gridCtx.lineTo(pos, gridCanvas.height);
        gridCtx.moveTo(0, pos);
        gridCtx.lineTo(gridCanvas.width, pos);
        gridCtx.stroke();
      }
    }
    resizeCanvas();
    window.addEventListener('resize', resizeCanvas);

    // Helpers (color gradients, rounded rect, empty‑cell check)
    function colorGradient(isSnake){
      hue = (hue + 2) % 360;
      if(isSnake){
        const c1 = `hsl(${hue},100%,50%)`,
              c2 = `hsl(${(hue+40)%360},100%,60%)`,
              g  = ctx.createLinearGradient(0, 0, canvas.width, canvas.height);
        g.addColorStop(0, c1);
        g.addColorStop(1, c2);
        return g;
      } else {
        const g = ctx.createRadialGradient(0,0,5, 0,0, gridSize*0.6);
        g.addColorStop(0, `hsl(${hue},100%,70%)`);
        g.addColorStop(1, `hsl(${(hue+60)%360},80%,40%)`);
        return g;
      }
    }
    function roundedRect(x,y,w,h,r){
      ctx.beginPath();
      ctx.moveTo(x+r,y);           ctx.lineTo(x+w-r,y);
      ctx.quadraticCurveTo(x+w,y,  x+w,y+r);
      ctx.lineTo(x+w,y+h-r);
      ctx.quadraticCurveTo(x+w,y+h, x+w-r,y+h);
      ctx.lineTo(x+r,y+h);
      ctx.quadraticCurveTo(x,y+h,   x,y+h-r);
      ctx.lineTo(x,y+r);
      ctx.quadraticCurveTo(x,y,     x+r,y);
      ctx.closePath();
      ctx.fill();
    }
    function isEmpty(x,y){
      return !snake.some(s=>s.x===x&&s.y===y)
          && !apples.some(a=>a.x===x&&a.y===y)
          && !powerUps.some(p=>p.x===x&&p.y===y);
    }

    // Apple spawning
    function spawnApples(){
      while(apples.length < maxApples){
        const p = {
          x: Math.floor(Math.random() * tileCount),
          y: Math.floor(Math.random() * tileCount),
          type: 'apple'
        };
        if(isEmpty(p.x, p.y)) apples.push(p);
      }
      
      // Occasionally spawn power-up (20% chance)
      if (powerUps.length === 0 && Math.random() < 0.2) {
        const types = Object.keys(POWERUP_TYPES);
        const type = types[Math.floor(Math.random() * types.length)];
        const p = {
          x: Math.floor(Math.random() * tileCount),
          y: Math.floor(Math.random() * tileCount),
          type: type,
          color: POWERUP_TYPES[type].color
        };
        if(isEmpty(p.x, p.y)) powerUps.push(p);
      }
    }

    // Effects (score pop‑up, particles, flash)
    function addScoreFx(x,y,amt){
      effects.score.push({
        x: x*gridSize + gridSize/2,
        y: y*gridSize + gridSize/2,
        alpha: 1, text: '+'+amt, size: 24
      });
    }
    function addParticles(x,y, color, count=12, size=6){
      for(let i=0;i<count;i++){
        effects.particles.push({
          x: x*gridSize + gridSize/2,
          y: y*gridSize + gridSize/2,
          dx: (Math.random()-0.5)*8,
          dy: (Math.random()-0.5)*8,
          alpha: 1, 
          size: Math.random()*size + (size/2),
          color: color || `hsla(${Math.random()*360},100%,60%,1)`
        });
      }
    }
    function updateEffects(){
      // Use reverse loops to safely remove items while iterating
      for(let i=effects.score.length-1; i>=0; i--){
        const e = effects.score[i];
        e.y -= 1.5;
        e.alpha -= 0.02;
        e.size += 0.3;
        if(e.alpha <= 0) effects.score.splice(i,1);
      }
      for(let i=effects.particles.length-1; i>=0; i--){
        const p = effects.particles[i];
        p.x += p.dx;
        p.y += p.dy;
        p.alpha -= 0.03;
        p.dy += 0.1; // gravity
        if(p.alpha <= 0) effects.particles.splice(i,1);
      }
    }
    function flashScore(){
      sb.classList.add('flash');
      setTimeout(()=> sb.classList.remove('flash'), 200);
      try {
        generateEatSound();
      } catch(e) {
        // Audio play might fail if not triggered by user interaction
      }
    }

    // Game update
    function update(){
      if(gameOver || isPaused) return;

      // Update power-up timer
      if (powerUpActive) {
        powerUpTimer -= interval;
        if (powerUpTimer <= 0) {
          POWERUP_TYPES[powerUpActive].reverse();
          powerUpActive = null;
          speedEl.textContent = Math.round(fps);
        }
      }

      // Prevent reversing direction
      if((nextVel.x !== -velocity.x || nextVel.y !== -velocity.y)
       &&(nextVel.x !== velocity.x  || nextVel.y !== velocity.y)) {
        velocity = nextVel;
      }

      const head = {
        x: (snake[0].x + velocity.x + tileCount) % tileCount,
        y: (snake[0].y + velocity.y + tileCount) % tileCount
      };

      // Add to snake trail
      snakeTrail.push({...snake[0]});
      if (snakeTrail.length > 5) snakeTrail.shift();

      // Check collision with self
      if(snake.some(p=>p.x===head.x && p.y===head.y)){
        gameOver = true;
        showGameOver();
        return;
      }

      snake.unshift(head);

      let ate = false;
      let powerUpCollected = false;
      
      // Check for apple collision
      for(let i=0; i<apples.length; i++){
        if(apples[i].x===head.x && apples[i].y===head.y){
          const now = Date.now();
          const timeBonus  = (now - lastAppleTime < 3000) ? 5 : 0;
          const comboBonus = comboCounter * 2;
          const gain      = 10 + timeBonus + comboBonus;
          score += gain;
          comboCounter++;
          lastAppleTime = now;
          scoreEl.textContent = score;
          if(score > highScore){
            highScore = score;
            localStorage.setItem('snakeHighScore', highScore);
            highEl.textContent = highScore;
          }
          addScoreFx(head.x, head.y, gain);
          addParticles(head.x, head.y, '#0f9', 20, 8);
          flashScore();
          apples.splice(i,1);
          spawnApples();
          ate = true;
          break;
        }
      }
      
      // Check for power-up collision
      for(let i=0; i<powerUps.length; i++){
        if(powerUps[i].x===head.x && powerUps[i].y===head.y){
          const type = powerUps[i].type;
          POWERUP_TYPES[type].effect();
          powerUpActive = type;
          powerUpTimer = powerUpDuration;
          addParticles(head.x, head.y, POWERUP_TYPES[type].color, 30, 10);
          try {
            generatePowerSound();
          } catch(e) {}
          powerUps.splice(i,1);
          powerUpCollected = true;
          speedEl.textContent = Math.round(fps);
          break;
        }
      }
      
      if(!ate && !powerUpCollected){
        comboCounter = 0;
        snake.pop();
      }
    }

    // Draw
    function draw(){
      ctx.clearRect(0, 0, canvas.width, canvas.height);

      // Draw pre-rendered grid
      ctx.drawImage(gridCanvas, 0, 0);

      // Draw snake trail
      for (let i = 0; i < snakeTrail.length; i++) {
        const t = snakeTrail[i];
        const px = t.x * gridSize, py = t.y * gridSize;
        const size = gridSize * (0.4 + (i * 0.12));
        const offset = (gridSize - size) / 2;
        
        ctx.save();
        ctx.globalAlpha = 0.3 - (i * 0.05);
        ctx.fillStyle = `hsl(${(hue + i*10) % 360}, 100%, 60%)`;
        ctx.shadowColor = '#0ff';
        ctx.shadowBlur = 15;
        roundedRect(px + offset, py + offset, size, size, 5);
        ctx.restore();
      }

      // Draw power-ups
      powerUps.forEach(p=>{
        const cx = p.x * gridSize + gridSize/2;
        const cy = p.y * gridSize + gridSize/2;
        ctx.save();
        ctx.translate(cx, cy);
        ctx.rotate(Date.now() / 1000);
        ctx.shadowColor = p.color;
        ctx.shadowBlur = 20;
        
        // Different shapes for different power-ups
        if (p.type === 'SPEED_BOOST') {
          // Lightning bolt
          ctx.fillStyle = p.color;
          ctx.beginPath();
          ctx.moveTo(-gridSize*0.2, -gridSize*0.3);
          ctx.lineTo(0, 0);
          ctx.lineTo(gridSize*0.2, gridSize*0.3);
          ctx.lineTo(0, gridSize*0.1);
          ctx.lineTo(gridSize*0.2, gridSize*0.4);
          ctx.lineTo(-gridSize*0.1, gridSize*0.4);
          ctx.lineTo(0, gridSize*0.1);
          ctx.lineTo(-gridSize*0.2, -gridSize*0.1);
          ctx.closePath();
          ctx.fill();
        } else {
          // Star
          ctx.fillStyle = p.color;
          ctx.beginPath();
          for (let i = 0; i < 10; i++) {
            const angle = i * Math.PI / 5;
            const radius = i % 2 === 0 ? gridSize * 0.3 : gridSize * 0.15;
            ctx.lineTo(Math.cos(angle) * radius, Math.sin(angle) * radius);
          }
          ctx.closePath();
          ctx.fill();
        }
        
        ctx.restore();
      });

      // Draw apples
      apples.forEach(a=>{
        const cx = a.x*gridSize + gridSize/2;
        const cy = a.y*gridSize + gridSize/2;
        ctx.save();
        ctx.translate(cx, cy);
        ctx.shadowColor = '#f44';
        ctx.shadowBlur = 18;
        ctx.fillStyle = colorGradient(false);
        ctx.beginPath();
        ctx.ellipse(0,0, gridSize*0.4, gridSize*0.55, Math.PI/6, 0, 2*Math.PI);
        ctx.fill();
        ctx.fillStyle = '#282';
        ctx.beginPath();
        ctx.ellipse(0, -gridSize*0.3, gridSize*0.15, gridSize*0.3, Math.PI/4, 0, 2*Math.PI);
        ctx.fill();
        ctx.restore();
      });

      // Draw snake
      snake.forEach((s,i)=>{
        const px = s.x*gridSize, py = s.y*gridSize;
        ctx.save();
        ctx.fillStyle = colorGradient(true);
        ctx.shadowColor = '#0ff';
        ctx.shadowBlur = (i===0 ? 25 : 18);
        roundedRect(px+2, py+2, gridSize-4, gridSize-4, 8);
        
        // Draw eyes on head
        if (i === 0) {
          ctx.fillStyle = '#000';
          // Left eye
          ctx.beginPath();
          ctx.arc(
            px + (velocity.x === 1 ? gridSize - 8 : velocity.x === -1 ? 8 : gridSize/2 - 4), 
            py + (velocity.y === 1 ? gridSize - 8 : velocity.y === -1 ? 8 : gridSize/2 - 4), 
            4, 0, Math.PI * 2
          );
          ctx.fill();
          
          // Right eye
          ctx.beginPath();
          ctx.arc(
            px + (velocity.x === 1 ? gridSize - 8 : velocity.x === -1 ? 8 : gridSize/2 + 4), 
            py + (velocity.y === 1 ? gridSize - 8 : velocity.y === -1 ? 8 : gridSize/2 + 4), 
            4, 0, Math.PI * 2
          );
          ctx.fill();
        }
        
        ctx.restore();
      });

      // Draw effects
      effects.particles.forEach(p=>{
        ctx.fillStyle = p.color.replace('hsla', 'rgba').replace(')', `,${p.alpha})`);
        ctx.beginPath();
        ctx.arc(p.x, p.y, p.size, 0, 2*Math.PI);
        ctx.fill();
      });
      effects.score.forEach(e=>{
        ctx.fillStyle = `rgba(0,255,150,${e.alpha})`;
        ctx.font = `bold ${e.size}px Arial`;
        ctx.textAlign = 'center';
        ctx.shadowColor = '#0f9';
        ctx.shadowBlur = 10;
        ctx.fillText(e.text, e.x, e.y);
      });
      
      // Draw active power-up indicator
      if (powerUpActive) {
        ctx.fillStyle = POWERUP_TYPES[powerUpActive].color;
        ctx.font = 'bold 16px Arial';
        ctx.textAlign = 'right';
        ctx.shadowColor = POWERUP_TYPES[powerUpActive].color;
        ctx.shadowBlur = 10;
        ctx.fillText(
          `POWER: ${Math.ceil(powerUpTimer/1000)}s`, 
          canvas.width - 10, 
          20
        );
      }
    }

    // Input handling
    let touchStart = null;
    const minSwipe = 30;

    canvas.addEventListener('touchstart', e=>{
      if(e.touches.length === 1) {
        touchStart = { x: e.touches[0].clientX, y: e.touches[0].clientY };
      }
    }, { passive: true });

    canvas.addEventListener('touchmove', e=>{
      if(!touchStart || isPaused) return;
      const dx = e.touches[0].clientX - touchStart.x;
      const dy = e.touches[0].clientY - touchStart.y;
      if(Math.abs(dx) > minSwipe || Math.abs(dy) > minSwipe){
        const dir = Math.abs(dx) > Math.abs(dy) ? (dx > 0 ? 'right' : 'left') : (dy > 0 ? 'down' : 'up');
        changeDir(dir);
        touchStart = null;
        
        // Vibrate on mobile
        if (navigator.vibrate) navigator.vibrate(50);
      }
    }, { passive: true });

    canvas.addEventListener('touchend', () => { touchStart = null; });

    btns.forEach(b => b.addEventListener('click', () => {
      if (!isPaused) changeDir(b.dataset.dir);
    }));

    // Keyboard support: arrows + WASD
    window.addEventListener('keydown', e => {
      if(gameOver || isPaused) return; // ignore input if game over or paused
      const keyMap = {
        ArrowUp: 'up',
        ArrowDown: 'down',
        ArrowLeft: 'left',
        ArrowRight: 'right',
        w: 'up',
        s: 'down',
        a: 'left',
        d: 'right',
        W: 'up',
        S: 'down',
        A: 'left',
        D: 'right',
        p: 'pause',
        P: 'pause',
        ' ': 'pause'
      };
      const action = keyMap[e.key];
      if(action) {
        e.preventDefault();
        if (action === 'pause') {
          togglePause();
        } else {
          changeDir(action);
        }
      }
    });

    function changeDir(dir){
      const map = { up:{x:0,y:-1}, down:{x:0,y:1}, left:{x:-1,y:0}, right:{x:1,y:0} };
      const nv = map[dir];
      if(nv && (nv.x !== -velocity.x || nv.y !== -velocity.y)) nextVel = nv;
    }

    // Pause functionality
    function togglePause() {
      isPaused = !isPaused;
      pauseBtn.textContent = isPaused ? '▶️ Resume' : '⏸️ Pause';
      pauseOverlay.classList.toggle('show', isPaused);
      if (!isPaused) game.focus();
    }

    // Game over UI and restart
    function showGameOver(){
      finalScoreEl.textContent = score;
      gameOverModal.classList.add('show');
      modalRestartBtn.focus();
      try {
        generateGameOverSound();
      } catch(e) {}
    }

    // Restart button handler
    function restartGame() {
      if (powerUpActive) {
        POWERUP_TYPES[powerUpActive].reverse();
      }
      initGame();
    }

    restartBtn.addEventListener('click', restartGame);
    modalRestartBtn.addEventListener('click', restartGame);

    // Difficulty change
    difficulty.addEventListener('change', function() {
      switch(this.value) {
        case 'easy': fps = 8; break;
        case 'medium': fps = 10; break;
        case 'hard': fps = 13; break;
        case 'insane': fps = 16; break;
      }
      interval = 1000 / fps;
      speedEl.textContent = fps;
      if (!gameOver && !isPaused) game.focus();
    });

    // Main loop with fixed FPS using delta accumulator
    function loop(ts=0){
      if(!lastTime) lastTime = ts;
      delta += ts - lastTime;
      lastTime = ts;

      while(delta >= interval){
        update();
        updateEffects();
        delta -= interval;
      }
      draw();
      requestAnimationFrame(loop);
    }

    // Start game
    initGame();
    requestAnimationFrame(loop);
  })();
  </script>
</body>
</html>