chore: tweak dark mode backgrounds

- make the darkest one a bit lighter (else it's just too dark)
- turn down saturation to give the whole thing a bit of a warmer feeling (the blue makes it overly cold)

Author: dummdidumm

packages/site-kit/src/lib/styles/tokens.css

@@ -143,12 +143,12 @@
 
 		--sk-back-hue: 220;
 
-		--sk-back-1: hsl(var(--sk-back-hue), 15%, 8%);
-		--sk-back-2: hsl(var(--sk-back-hue), 15%, 15%);
-		--sk-back-3: hsl(var(--sk-back-hue), 15%, 12%);
-		--sk-back-4: hsl(var(--sk-back-hue), 15%, 22%);
-		--sk-back-5: hsl(var(--sk-back-hue), 15%, 25%);
-		--sk-back-6: hsl(var(--sk-back-hue), 15%, 32%);
+		--sk-back-1: hsl(var(--sk-back-hue), 5%, 10%);
+		--sk-back-2: hsl(var(--sk-back-hue), 5%, 15%);
+		--sk-back-3: hsl(var(--sk-back-hue), 5%, 12%);
+		--sk-back-4: hsl(var(--sk-back-hue), 5%, 22%);
+		--sk-back-5: hsl(var(--sk-back-hue), 5%, 25%);
+		--sk-back-6: hsl(var(--sk-back-hue), 5%, 32%);
 		--sk-back-translucent: hsla(0, 0%, 100%, 0.1);
 		--sk-theme-1-hsl: 12, 94%, 62%;
 		--sk-text-1: hsl(var(--sk-back-hue), 10%, 90%);