Examine source code of classic gray theme

{
  "theme": {
    "colors": {
      "frame": "#404040",
      "tab_background_text": "#d8d8d8",
      "tab_selected": "#282828",
      "toolbar": "#505050",
      "tab_text": "#ffffff",
      "ntp_background": "#323232",
      "ntp_text": "#ffffff",
      "sidebar_border": "#272727",
      "sidebar_highlight": "#707070",
      "sidebar_text": "#d8d8d8",
      "sidebar_highlight_text": "#ffffff",
      "icons": "#aeaeae",
      "icons_attention": "#ffffff",
      "sidebar": "#353535",
      "popup": "#353535",
      "popup_border": "#272727",
      "popup_highlight": "#707070",
      "popup_highlight_text": "#ffffff",
      "popup_text": "#d8d8d8",
      "tab_line": "#282828",
      "toolbar_bottom_separator": "#282828",
      "toolbar_field": "#3c3c3c",
      "toolbar_field_text": "#ffffff",
      "bookmark_text": "#ffffff",
      "toolbar_top_separator": "#282828",
      "tab_loading": "#ffffff",
      "toolbar_vertical_separator": "#828282",
      "toolbar_field_separator": "#828282",
      "tab_background_separator": "#bebebe",
      "toolbar_field_border_focus": "#282828",
      "toolbar_field_text_focus": "#ffffff",
      "toolbar_field_focus": "#3c3c3c",
      "toolbar_field_border": "#282828",
      "button_background_hover": "#828282",
      "button_background_active": "#464646"
    }
  },
  "name": "Classic Grey theme",
  "manifest_version": 2,
  "version": "1.1"
}