diff --git a/src/components/blog/PostBodyClient.tsx b/src/components/blog/PostBodyClient.tsx
index c5691e2..465db93 100644
--- a/src/components/blog/PostBodyClient.tsx
+++ b/src/components/blog/PostBodyClient.tsx
@@ -105,6 +105,9 @@ export default function PostBodyClient(props: PostBodyClientProps) {
       const pre = codeBlock.parentElement;
       if (!pre) return;
 
+      // Skip mermaid diagrams
+      if (pre.dataset.type === "mermaid") return;
+
       // Check if already processed (has header with copy button)
       const existingHeader = pre.previousElementSibling;
       if (