Update themes.json

Author: Kess-UwU

themes.json

@@ -2299,4 +2299,16 @@
     "stargazers_count": 35,
     "avatar": "https://avatars.githubusercontent.com/u/6378995?v=4"
   }
-]
+  {
+    "title": "Seal mint",
+    "link": "https://github.com/Kess-UwU/Seal-Mint",
+    "description": "Minimal mint&blue theme for Firefox",
+    "image": "https://github.com/Kess-UwU/Seal-Mint/blob/1db0c345529d9f44fd4f6d543b5e396ed89a078e/preview(1).png",
+    "tags": [ "Kess-UwU",
+      "Mint&Blue",
+      "blue",
+      "mint",
+      "minimal"],
+    "repository": "https://github.com/Kess-UwU/Seal-Mint"
+  }
+]