Examine source code of Jikan

{
  "name": "Jikan",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "background.png"
    },
    "colors": {
      "frame": "rgba(12, 12, 12, 0.95)",
      "tab_background_text": "rgba(0, 98, 255, 0.85)",
      "toolbar": "rgba(12, 12, 12, 0.85)",
      "bookmark_text": "rgba(255, 0, 0, 1)",
      "toolbar_field": "rgba(12, 12, 12, 1)",
      "toolbar_field_text": "rgba(0, 100, 255, 1)"
    }
  }
}