Source

mobile-demo-set / static / sdk / resources / themes / stylesheets / sencha-touch / default / widgets / _map.scss

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.x-map {
  background-color: #edeae2; //GMap tan background
  * {
      -webkit-box-sizing: content-box;
      box-sizing: content-box;
  }
}

.x-mask-map {
  background: transparent !important;
}