diff --git a/source/js/third-party/tags/mermaid.js b/source/js/third-party/tags/mermaid.js
index 3831995..9623dc5 100644
--- a/source/js/third-party/tags/mermaid.js
+++ b/source/js/third-party/tags/mermaid.js
@@ -10,7 +10,14 @@ document.addEventListener('page:loaded', () => {
         const newElement = document.createElement('div');
         newElement.innerHTML = element.innerHTML;
         newElement.className = element.className;
-        element.parentNode.replaceChild(newElement, element);
+        const parent = element.parentNode;
+        // Fix issue #347
+        // Support mermaid inside backtick code block
+        if (parent.matches('pre')) {
+          parent.parentNode.replaceChild(newElement, parent);
+        } else {
+          parent.replaceChild(newElement, element);
+        }
       });
       mermaid.initialize({
         theme    : CONFIG.darkmode && window.matchMedia('(prefers-color-scheme: dark)').matches ? CONFIG.mermaid.theme.dark : CONFIG.mermaid.theme.light,