manifest.json (Chrome extension) attribute "theme_color" don't work

A few days ago I created a manifest.json file for my website but the "theme_color" attribute does not work, which causes the navigation bar to change in the Google Chrome mobile app

This is the code

{
"short_name": "ITCHA",
"name": "Instituto Tecnológico de Chalatenango",
"theme_color": "#D9A300",
"description": "Innovando la Educación Técnica Superior",
"lang": "es",
"dir": "rtl",
"background_color": "#D9A300",
"icons": [
  {
    "src": "images/logos/launcher-icon-1x.png",
    "type": "image/png",
    "sizes": "48x48"
  },
  {
    "src": "images/logos/launcher-icon-2x.png",
    "type": "image/png",
    "sizes": "96x96"
  },
  {
    "src": "images/logos/launcher-icon-4x.png",
    "type": "image/png",
    "sizes": "192x192"
  }
],
"start_url": "index.php",
"related_applications": [{
  "platform": "web",
  "url": "http://ift.tt/2uXZ8An"
}, {
  "platform": "play",
  "url": "http://ift.tt/2wnRrHe"
}],
"gcm_sender_id": "103953800507"

}

The web site is www.itcha.edu.sv