fix(mermaid-viewer): Improve error message on diagram rendering failure

diff --git a/content/mermaid-viewer/head.html b/content/mermaid-viewer/head.html
index b737ba049336044d88a3c0f07a01c8b21373f779..187b41098d03e164ba9e9946c8aba7c6d732a861 100644 (file)
--- a/content/mermaid-viewer/head.html
+++ b/content/mermaid-viewer/head.html
@@ -149,7 +149,8 @@
                     this.centerDiagram();
                 }).catch(error => {
                     console.error("Mermaid rendering error for diagram:", this.mermaidCode, error);
-                    this.diagram.innerHTML = `<p style="color: red; padding: 10px;">Error rendering diagram. Check console.</p>`;
+                    // Use BookStack's negative color variable and provide a clearer message for debugging.
+                    this.diagram.innerHTML = `<p style="color: var(--color-neg); padding: 10px;">Error rendering diagram. Check browser console for details.</p>`;
                 });
             };