minor color fix

Author: dburles

packages/docs/src/pages/theme-spec.mdx

@@ -37,7 +37,7 @@ A theme does not require that all these fields be present and can include additi
     primary: '#07c',
     secondary: '#05a',
     accent: '#609',
-    muted: '#f6f6f6f',
+    muted: '#f6f6f6',
   },
   fonts: {
     body: 'system-ui, sans-serif',