fix private overlay color in dark mode

Author: westnordost

Main.kt

@@ -54,7 +54,7 @@ val themeNight = Colors(
     textOutline = "#2e2e48",
     textWater = "#2e2e48",
     textWaterOutline = "#ccf",
-    privateOverlay = "#f3dacd",
+    privateOverlay = "#3d364e",
     hillshadeLight = "hsl(240, 30%, 50%)",
     hillshadeShadow = "hsl(240, 80%, 0%)",
     onewayArrow = "#ccf"