Examine source code of Summertime...

{
  "theme": {
    "images": {
      "theme_frame": "Summertime.Persona1.png"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000"
    }
  },
  "version": "2.0",
  "name": "Summertime...",
  "manifest_version": 2,
  "description": "<a href=\"https://outgoing.prod.mozaws.net/v1/e36ebefb85198ec1511edc470caf1dcf497977a6496a0c8ac1c723318432a67c/http%3A//danielbevisportfolio.limewebs.com/Gallery/illustrations.htm\" rel=\"nofollow\">http://danielbevisportfolio.limewebs.com/Gallery/illustrations.htm</a>\n\nA fun combination of colours that remind me of summer. \n\nThe typeface is VAL from Fontfabric.\nThe water [and sand] streaks are made out of a chocolate spread brush I made awhile ago, and infused with turquoise colours."
}