Examine source code of Rem & Ram Re:zero (Semi-Dark mode)

{
  "manifest_version": 2,
  "version": "2.2",
  "name": "Ram Rem",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png",
        "images/1.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top",
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat",
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(9, 80, 107, 0.29)",
      "toolbar_text": "rgb(35, 201, 245)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(249, 64, 64)",
      "toolbar_field": "rgba(87, 8, 9, 0.34)",
      "toolbar_field_text": "rgb(47, 255, 249)",
      "tab_line": "rgb(104, 158, 255)",
      "popup": "rgba(10, 10, 41, 0.92)",
      "popup_text": "rgb(200, 42, 42)",
      "button_background_active": "rgba(29, 87, 111, 0.57)",
      "button_background_hover": "rgba(10, 186, 255, 0.32)",
      "frame_inactive": "rgb(12, 7, 7)",
      "icons_attention": "rgb(198, 14, 14)",
      "icons": "rgb(255, 55, 94)",
      "ntp_text": "rgb(255, 255, 255)",
      "popup_border": "rgb(246, 37, 37)",
      "popup_highlight_text": "rgb(207, 78, 95)",
      "popup_highlight": "rgba(75, 136, 234, 0.41)",
      "sidebar_border": "rgb(234, 15, 15)",
      "sidebar_highlight_text": "rgba(246, 130, 130, 0.88)",
      "sidebar_highlight": "rgba(249, 64, 64, 0.38)",
      "sidebar_text": "rgb(24, 121, 255)",
      "sidebar": "rgb(0, 0, 0)",
      "tab_background_separator": "rgba(255, 0, 0, 0.63)",
      "tab_loading": "rgba(15, 92, 223, 0.32)",
      "tab_selected": "rgba(26, 108, 246, 0.32)",
      "tab_text": "rgb(96, 231, 255)",
      "toolbar_bottom_separator": "rgba(255, 74, 74, 0.63)",
      "toolbar_field_border_focus": "rgba(94, 19, 255, 0.22)",
      "toolbar_field_border": "rgba(36, 94, 200, 0.22)",
      "toolbar_field_focus": "rgba(43, 7, 7, 0.39)",
      "toolbar_field_highlight_text": "rgba(255, 7, 0, 0.72)",
      "toolbar_field_highlight": "rgba(26, 58, 164, 0.7)",
      "toolbar_field_separator": "rgba(72, 96, 181, 0.39)",
      "toolbar_field_text_focus": "rgba(0, 44, 190, 0.7)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{715c7e1f-0004-450c-bfa7-6be090329cb6}"
    }
  }
}