1 files changed, 5 insertions, 2 deletions
diff --git a/nuldoc-src/docbook/to_html.ts b/nuldoc-src/docbook/to_html.ts
index 6788158..64d3492 100644
--- a/nuldoc-src/docbook/to_html.ts
+++ b/nuldoc-src/docbook/to_html.ts
@@ -192,6 +192,8 @@ function transformProgramListingElement(doc: Document) {
     }
 
     n.name = "pre";
+    const preClass = n.attributes.get("class");
+    n.attributes.set("class", preClass ? preClass + " highlight" : "highlight");
     const codeElement: Element = {
       kind: "element",
       name: "code",
@@ -209,12 +211,13 @@ function transformLiteralLayoutElement(doc: Document) {
     }
 
     n.name = "pre";
-    const children = n.children;
+    const preClass = n.attributes.get("class");
+    n.attributes.set("class", preClass ? preClass + " highlight" : "highlight");
     const codeElement: Element = {
       kind: "element",
       name: "code",
       attributes: new Map(),
-      children: children,
+      children: n.children,
     };
     n.children = [codeElement];
   });