chore: fix docs codeblock style

Author: YousefED

docs/styles.css

@@ -8,5 +8,10 @@ config. This is a problem because ShadCN relies on CSS variables which are only
 scoped to the editor, and are undefined when Nextra components try to use them.
 Seems like this only affects border radius in the demos though. */
 body {
-    --radius: 0.5rem;
-}
+  --radius: 0.5rem;
+}
+
+/* nextra's contain:paint breaks the code block language selector*/
+.ProseMirror pre {
+  contain: none;
+}