Dark mode support and much other stuff

src/js/game/themes/dark.json

@@ -10,6 +10,10 @@
             "red": "#4a3d3f",
             "green": "#3e4a3d",
             "blue": "#35384a"
+        },
+        "chunkOverview": {
+            "empty": "#444856",
+            "filled": "#646b7d"
         }
     },
 

src/js/game/themes/light.json

@@ -10,6 +10,11 @@
             "red": "#ffbfc1",
             "green": "#cbffc4",
             "blue": "#bfdaff"
+        },
+
+        "chunkOverview": {
+            "empty": "#a6afbb",
+            "filled": "c5ccd6"
         }
     },