Apply suggestions from code review

Co-authored-by: Jesse Tan <[email protected]>

Author: Blendify

src/sass/_theme_rst.sass

@@ -483,7 +483,10 @@
     border-radius: $base-line-height / 6
     padding: $base-line-height / 10 $base-line-height / 4
     margin: auto 0
-  kbd, .kbd
+  :not(kbd) > kbd,
+  :not(kbd) > .kbd,
+  :not(.kbd) > kbd,
+  :not(.kbd) > .kbd
     color: inherit
     font-size: 80%
     background-color: lighten($text-light, 30%)