Examine source code of ayu

{
  "manifest_version": 2,
  "version": "2.0",
  "name": "ayu",
  "description": "Firefox theme with the ayu color scheme",
  "theme": {
    "colors": {
      "tab_background_separator": "#3E4B59",
      "tab_background_text": "#14191F",
      "toolbar": "#14191F",
      "textcolor": "#5C6773",
      "tab_line": "#14191F",
      "tab_loading": "#3E4B59",
      "toolbar_top_separator": "#14191F",
      "toolbar_vertical_separator": "#3E4B59",
      "toolbar_bottom_separator": "#14191F",
      "toolbar_field": "#14191F",
      "toolbar_field_text": "#3E4B59",
      "toolbar_field_border": "#151A1E",
      "toolbar_field_separator": "#3E4B59",
      "toolbar_field_focus": "#0F1419",
      "toolbar_field_text_focus": "#E6E1CF",
      "toolbar_field_border_focus": "#253340",
      "button_background_active": "#253340",
      "button_background_hover": "#253340",
      "icons": "#3E4B59",
      "icons_attention": "#3E4B59",
      "popup": "#14191F",
      "popup_text": "#5C6773",
      "popup_border": "#14191F",
      "popup_highlight": "#3E4B59",
      "popup_highlight_text": "#E6E1CF",
      "frame": "#0F1419"
    }
  }
}