adjust dark mode colors of default theme

src/client/styles/scss/theme/_reboot-bootstrap-colors.scss

@@ -205,15 +205,15 @@ a {
 // causes specificity issues in many other styles that are too complex to fix.
 // See https://github.com/twbs/bootstrap/issues/19402
 
-a:not([href]) {
-  color: inherit;
-  // text-decoration: none;
+// a:not([href]) {
+//   color: inherit;
+//   text-decoration: none;
 
-  @include hover() {
-    color: inherit;
-    // text-decoration: none;
-  }
-}
+//   @include hover() {
+//     color: inherit;
+//     text-decoration: none;
+//   }
+// }
 
 //
 // Code

src/client/styles/scss/theme/default.scss

@@ -57,9 +57,8 @@ html[dark] {
   $bgcolor-card: darken($basecolor, 5%);
 
   // Font colors
-  $color-global: lighten($basecolor, 35%);
-  $color-header: lighten($basecolor, 45%);
-  $color-link: lighten($basecolor, 45%);
+  $color-global: lighten($basecolor, 60%);
+  $color-header: desaturate($primary, 20%);
   $color-link-hover: lighten($color-link, 10%);
   $color-link-wiki: saturate($color-global, 20%);
   $color-link-wiki-hover: darken($color-link-wiki, 5%);