Toggle">Airplanes</label></div>
        <button class="btn primary" id="save">Save picture</button>
      </div>
    </div>
  </div>

  <div class="footer">Tip: Drag to paint. Try switching brushes. Press <span class="kbd">S</span> to save.</div>

  <script>
    const canvas = document.getElementById('sky');
    const ctx = canvas.getContext('2d');
    let W = canvas.width = window.innerWidth;
    let H = canvas.height = window.innerHeight;
    const DPR = Math.max(1, Math.min(2, window.devicePixelRatio || 