function updateDeviceFrameSize() {
  if (!devicePicker || !devicePicker.value) return;
  const [width, height] = devicePicker.value.split(',');
  if (width && height) {
    document.documentElement.style.setProperty('--device-width', `${width}px`);
    document.documentElement.style.setProperty('--device-height', `${height}px`);
  }
}