Examine source code of vivid colours

{
  "name": "blue",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "blue.png"
    },
    "colors": {
      "frame": "rgba(52, 89, 149, 1)",
      "tab_background_text": "rgba(202, 21, 81, 1)",
      "toolbar": "rgba(3, 206, 194, 1)",
      "bookmark_text": "rgba(202, 21, 81, 1)",
      "toolbar_field": "rgba(234, 196, 53, 1)",
      "toolbar_field_text": "rgba(202, 21, 81, 1)"
    }
  }
}