Update pages.mdx

Author: mintlify[bot]

pages.mdx

@@ -93,6 +93,17 @@ mode: "center"
 ---
 ```
 
+### Frame
+
+Frame mode provides a custom layout similar to custom mode but preserves the sidebar display. This mode allows for custom HTML and components while maintaining navigation accessibility. Frame mode is only available for specific themes, including "aspen".
+
+```yaml
+---
+title: "Frame page title"
+mode: "frame"
+---
+```
+
 ## API pages
 
 Create interactive API playgrounds by adding an API specification to your frontmatter, `api` or `openapi`.