Examine source code of Pink Theme Base Gradient

{
  "manifest_version": 3,
  "name": "Pink Theme Base",
  "version": "1.0.0",
  "description": "Enterprise-grade private Firefox theme featuring a cute pink setup.",
  "browser_specific_settings": {
    "gecko": {
      "id": "pink-theme-base-835691@local.dev",
      "strict_min_version": "109.0"
    }
  },
  "theme": {
    "images": {
      "theme_frame": "assets/images/empty.png",
      "additional_backgrounds": [
        "assets/images/gradient_bg.png"
      ]
    },
    "colors": {
      "frame": "#D38C9D",
      "tab_background_text": "#000000",
      "toolbar": "#FFF0F5",
      "bookmark_text": "#000000",
      "toolbar_text": "#000000",
      "tab_selected": "#F7DAE7",
      "tab_text": "#000000",
      "tab_line": "#D38C9D",
      "toolbar_field": "#F7DAE7",
      "toolbar_field_focus": "#F7DAE7",
      "toolbar_field_text": "#000000",
      "popup": "#F7DAE7",
      "popup_text": "#000000",
      "popup_border": "#D38C9D",
      "ntp_background": "#F7DAE7",
      "ntp_text": "#000000"
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "left top"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    }
  }
}