Fixed tab boxes

Author: bastianeicher

mkdocs.yml

@@ -26,7 +26,8 @@ markdown_extensions:
   - def_list
   - admonition
   - pymdownx.highlight
-  - pymdownx.tabbed
+  - pymdownx.tabbed:
+      alternate_style: true
   - pymdownx.superfences
   - pymdownx.emoji:
       emoji_index: !!python/name:materialx.emoji.twemoji