fix: 🐛 CSS was wrongly placed in root .scss file (#192)

# Description

It seems like the custom styles file in not shipped with the extension.
Putting the rules in the brand file seems to work locally and I see
there is other css there as well. Worked for me locally too.

This PR needs a quick review.

Author: joelostblom

_extensions/seedcase-theme/_brand.yml

@@ -165,3 +165,14 @@ defaults:
       :is(h3, h4, h5, h6, dt) code {
         font-weight: bold;
       }
+
+      // Color built-ins the same as regular variables
+      // since we sometimes use built-in names as parameter names
+      span.bu {
+        color: inherit !important
+      }
+      // Color terminal executables the same as regular variables
+      // since the default has low contrast and is hard to see
+      span.ex {
+        color: inherit !important
+      }

_quarto.yml

@@ -24,7 +24,6 @@ format:
   seedcase-theme-html:
     theme:
       - brand
-      - custom-styles.scss
 
 editor:
   markdown: