Examine source code of Opera Dark

{
  "manifest_version": 2,
  "version": "5.0",
  "name": "Opera Dark",
  "theme": {
    "colors": {
      "toolbar": "#2a343d",
      "tab_line": "#2a343d",
      "tab_text": "#ffffff",
      "bookmark_text": "#e6e9eb",
      "frame": "#1a1e22",
      "frame_inactive": "#1a1e22",
      "tab_background_text": "#d9d9d9",
      "toolbar_field": "#2a343d",
      "toolbar_field_text": "#ffffff",
      "toolbar_field_text_focus": "#ffffff",
      "toolbar_field_focus": "#2a343d",
      "toolbar_field_border": "#2a343d",
      "toolbar_field_border_focus": "#60899e",
      "toolbar_field_highlight": "#96ddff",
      "toolbar_field_highlight_text": "#000000",
      "toolbar_field_separator": "#8c8d8f",
      "toolbar_text": "#e6e9eb",
      "toolbar_top_separator": "#2a343d",
      "toolbar_bottom_separator": "#101214",
      "toolbar_vertical_separator": "#2a343d",
      "tab_background_separator": "#54575a",
      "popup": "#171b1f",
      "popup_text": "#fafafa",
      "popup_border": "#3e4852",
      "popup_highlight": "#96ddff",
      "popup_highlight_text": "#000000",
      "tab_loading": "#828a8f",
      "tab_selected": "#2a343d",
      "sidebar": "#171b1f",
      "sidebar_highlight": "#354a55",
      "sidebar_highlight_text": "#ffffff",
      "sidebar_text": "#fafafa",
      "sidebar_border": "#000000",
      "button_background_active": "#1d2329",
      "button_background_hover": "#222a31",
      "icons": "#e6e9eb",
      "icons_attention": "#ff8d85",
      "ntp_background": "#1c1d1f",
      "ntp_link": "#ededed",
      "ntp_text": "#ededed"
    }
  }
}