Examine source code of Classic theme

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Classic theme (with menu bar)",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png",
        "images/1.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "left top",
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat",
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(212, 208, 200)",
      "toolbar_text": "rgb(0, 0, 0)",
      "frame": "rgb(212, 208, 200)",
      "tab_background_text": "rgb(0, 0, 0)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgb(255, 255, 255)",
      "popup": "rgb(255, 255, 225)",
      "popup_text": "rgb(0, 0, 0)",
      "button_background_active": "rgb(255, 255, 255)",
      "button_background_hover": "rgb(225, 225, 225)",
      "frame_inactive": "rgb(128, 128, 128)",
      "icons_attention": "rgb(10, 36, 106)",
      "icons": "rgb(0, 0, 0)",
      "popup_border": "rgb(128, 128, 128)",
      "popup_highlight_text": "rgb(255, 255, 255)",
      "popup_highlight": "rgb(10, 36, 106)",
      "sidebar_border": "rgb(0, 0, 0)",
      "sidebar_highlight_text": "rgb(255, 255, 255)",
      "sidebar_highlight": "rgb(10, 36, 106)",
      "sidebar_text": "rgb(0, 0, 0)",
      "sidebar": "rgb(212, 208, 200)",
      "tab_background_separator": "rgb(0, 0, 0)",
      "tab_selected": "rgb(212, 208, 200)",
      "toolbar_bottom_separator": "rgb(0, 0, 0)",
      "toolbar_field_border_focus": "rgb(0, 0, 0)",
      "toolbar_field_border": "rgb(0, 0, 0)",
      "toolbar_field_focus": "rgb(255, 255, 255)",
      "toolbar_field_highlight_text": "rgb(255, 255, 255)",
      "toolbar_field_highlight": "rgb(10, 36, 106)",
      "toolbar_field_separator": "rgb(0, 0, 0)",
      "toolbar_field_text_focus": "rgb(0, 0, 0)",
      "toolbar_top_separator": "rgb(128, 128, 128)",
      "toolbar_vertical_separator": "rgb(0, 0, 0)",
      "tab_loading": "rgb(255, 255, 255)"
    }
  }
}