Dynamic brand theming

merchant-config.json

[
  {
    "id": "merchant1",
    "brandColor": "#800080",
    "secondaryColor": "#FFA500",
    "bodyBackgroundColor": "#F2E6F2"
  },
  {
    "id": "merchant2",
    "brandColor": "#FF69B4",
    "secondaryColor": "#808080",
    "bodyBackgroundColor": "#FFF0F8"
  },
  {
    "id": "merchant3",
    "brandColor": "#FF0000",
    "secondaryColor": "#4B0082",
    "bodyBackgroundColor": "#FFE6E6"
  }
]