Fix dark mode contrast of .text-muted (#3319)

.changeset/fix-dark-muted-contrast.md

@@ -0,0 +1,5 @@
+---
+"@tabler/core": patch
+---
+
+Fixed dark mode contrast of `.text-muted` and other `muted` theme color utilities with a lighter `--tblr-muted` value.

core/scss/layout/_root.scss

@@ -33,6 +33,7 @@
   --link-hover-color: light-dark(#{mix-color-css(var(--black), var(--link-color), 20%)}, #{mix-color-css(var(--white), var(--link-color), 20%)});
 
   --secondary: light-dark(var(--gray-500), var(--gray-400));
+  --muted: light-dark(var(--gray-500), var(--gray-400));
   --tertiary: var(--gray-400);
 
   --border-color: light-dark(#{$border-color}, var(--gray-700));