diff --git a/src/lib/processHtml.ts b/src/lib/processHtml.ts
index 5ea4b32..0544e2e 100644
--- a/src/lib/processHtml.ts
+++ b/src/lib/processHtml.ts
@@ -1,5 +1,5 @@
-import { JSDOM } from "jsdom";
-import { createHighlighter } from "shiki";
+import {JSDOM} from "jsdom";
+import {createHighlighter} from "shiki";
 
 const DEFAULT_THEME = "github-dark-dimmed";
 
@@ -35,6 +35,15 @@ const loadedLangs = new Set<string>(["text"]);
 
 const supportedSet = new Set<string>(SUPPORTED_LANGS);
 
+const LANG_MAP: Record<string, string> = {
+  markup: "html",
+  html: "html",
+};
+
+const normalizeLang = (lang: string): string => {
+  return LANG_MAP[lang] || lang;
+};
+
 const ensureLangLoaded = async (lang: string): Promise<string> => {
   if (lang === "text" || loadedLangs.has(lang)) return lang;
   if (!supportedSet.has(lang)) return "text";
@@ -55,18 +64,20 @@ async function processCodeBlocks(document: Document) {
     if (!preEl || preEl.tagName !== "PRE") continue;
 
     const codeContent = codeBlock.textContent || "";
-    let lang = "text";
-    for (const cls of codeBlock.classList) {
+    let rawLang = "text";
+    for (const cls of preEl.classList) {
       if (cls.startsWith("language-")) {
-        lang = cls.slice("language-".length);
+        rawLang = cls.slice("language-".length);
         break;
       }
     }
 
-    lang = await ensureLangLoaded(lang);
+    const lang = normalizeLang(rawLang);
+
+    const loadedLang = await ensureLangLoaded(lang);
 
     const highlighted = highlighter.codeToHtml(codeContent, {
-      lang,
+      lang: loadedLang,
       theme: DEFAULT_THEME,
     });