Examine source code of Sweet Dreams...

{
  "theme": {
    "images": {
      "theme_frame": "SweetDreams_header_byLisa.jpg"
    },
    "colors": {
      "frame": "#ffffff",
      "tab_background_text": "#336666"
    }
  },
  "version": "2.0",
  "name": "Sweet Dreams...",
  "manifest_version": 2,
  "description": "background design, soft muted colors of mint, mauve, teal, beige, and gray swirling together in a billowy cloud\n\nchild friendly persona\n\nPersonas by LisaAtTheBeach"
}