diff --git a/sisvietnamvn_main/src/main/java/com/sisvietnamvn/web/controller/manage/ManageSnippetController.java b/sisvietnamvn_main/src/main/java/com/sisvietnamvn/web/controller/manage/ManageSnippetController.java
index eb57e63a..2265dbf8 100644
--- a/sisvietnamvn_main/src/main/java/com/sisvietnamvn/web/controller/manage/ManageSnippetController.java
+++ b/sisvietnamvn_main/src/main/java/com/sisvietnamvn/web/controller/manage/ManageSnippetController.java
@@ -63,4 +63,20 @@ public class ManageSnippetController {
         redirectAttributes.addFlashAttribute("successMessage", "Snippet deleted successfully.");
         return "redirect:/manage/snippets";
     }
+    @PostMapping("/{id}/duplicate")
+    public String duplicateSnippet(@PathVariable Long id, RedirectAttributes redirectAttributes) {
+        return snippetService.findById(id).map(snippet -> {
+            HtmlSnippet duplicated = new HtmlSnippet();
+            duplicated.setName(snippet.getName() + " (Copy)");
+            duplicated.setSlug(snippet.getSlug() + "-copy-" + System.currentTimeMillis());
+            duplicated.setContent(snippet.getContent());
+            duplicated.setActive(false);
+            HtmlSnippet saved = snippetService.save(duplicated);
+            redirectAttributes.addFlashAttribute("successMessage", "Snippet duplicated successfully.");
+            return "redirect:/manage/snippets/" + saved.getId() + "/edit";
+        }).orElseGet(() -> {
+            redirectAttributes.addFlashAttribute("errorMessage", "Snippet not found.");
+            return "redirect:/manage/snippets";
+        });
+    }
 }
diff --git a/sisvietnamvn_main/src/main/resources/templates/manage/snippets/form.html b/sisvietnamvn_main/src/main/resources/templates/manage/snippets/form.html
index fe05fd25..4156bd90 100644
--- a/sisvietnamvn_main/src/main/resources/templates/manage/snippets/form.html
+++ b/sisvietnamvn_main/src/main/resources/templates/manage/snippets/form.html
@@ -158,6 +158,9 @@
                                 <!-- Raw Textarea (hidden by default) -->
                                 <textarea class="form-control" id="snippetContent" name="content" th:text="*{content}" rows="20" style="font-family: monospace; display: none;"></textarea>
                                 
+                                <!-- Monaco Editor Container -->
+                                <div id="monacoEditorContainer" style="width: 100%; height: 75vh; min-height: 550px; border: 1px solid #d1d3e2; border-radius: 0.35rem; display: none;"></div>
+                                
                                 <!-- Visual Builder Container -->
                                 <div id="gjs-editor-wrap">
                                     <div class="panel__top">
@@ -220,29 +223,8 @@
         <!-- JS-Beautify for formatting HTML -->
         <script src="https://cdnjs.cloudflare.com/ajax/libs/js-beautify/1.14.7/beautify-html.min.js"></script>
         
-        <!-- CodeMirror JS for syntax highlighting -->
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/codemirror.min.js"></script>
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/mode/xml/xml.min.js"></script>
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/mode/css/css.min.js"></script>
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/mode/javascript/javascript.min.js"></script>
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/mode/htmlmixed/htmlmixed.min.js"></script>
-
-        <!-- CodeMirror Addons for VS Code-like experience -->
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/addon/edit/closetag.min.js"></script>
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/addon/edit/closebrackets.min.js"></script>
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/addon/edit/matchbrackets.min.js"></script>
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/addon/edit/matchtags.min.js"></script>
-        
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/addon/search/searchcursor.min.js"></script>
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/addon/search/search.min.js"></script>
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/addon/dialog/dialog.min.js"></script>
-        
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/keymap/sublime.min.js"></script>
-
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/addon/fold/foldcode.min.js"></script>
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/addon/fold/foldgutter.min.js"></script>
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/addon/fold/xml-fold.min.js"></script>
-        <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.13/addon/fold/brace-fold.min.js"></script>
+        <!-- Monaco Editor JS -->
+        <script src="https://cdnjs.cloudflare.com/ajax/libs/monaco-editor/0.41.0/min/vs/loader.min.js"></script>
 
         <script>
         document.addEventListener('DOMContentLoaded', function() {
@@ -675,9 +657,13 @@
                 editor.setComponents(existingContent);
             }
 
-            var cmEditor = null;
+            var monacoEditor = null;
             var isGrapesJsModified = false;
+            var monacoContainer = document.getElementById('monacoEditorContainer');
             
+            // Configure Monaco
+            require.config({ paths: { 'vs': 'https://cdnjs.cloudflare.com/ajax/libs/monaco-editor/0.41.0/min/vs' }});
+
             // Track if user made visual changes
             editor.on('change:changesCount', function() {
                 isGrapesJsModified = true;
@@ -689,7 +675,6 @@
                     var rawOutput;
                     
                     if (isGrapesJsModified) {
-                        // User made visual changes, pull from GrapesJS
                         var html = editor.getHtml();
                         var css = editor.getCss();
                         var combined = html + (css && css.trim() !== '' && css.trim() !== '* { box-sizing: border-box; } body {margin: 0;}' ? '<style>' + css + '</style>' : '');
@@ -700,61 +685,39 @@
                             preserve_newlines: true
                         });
                     } else {
-                        // User didn't make visual changes, KEEP IT RAW exactly as it was
                         rawOutput = textArea.value;
                     }
                     
                     textArea.value = rawOutput;
                     gjsWrap.style.display = 'none';
-                    // We don't display textArea because CodeMirror handles the UI
                     textArea.style.display = 'none';
+                    monacoContainer.style.display = 'block';
                     
-                    // Initialize CodeMirror if not already
-                    if (!cmEditor) {
-                        cmEditor = CodeMirror.fromTextArea(textArea, {
-                            mode: "htmlmixed",
-                            theme: "monokai",
-                            lineNumbers: true,
-                            matchBrackets: true,
-                            matchTags: {bothTags: true},
-                            autoCloseTags: true,
-                            autoCloseBrackets: true,
-                            indentUnit: 4,
-                            lineWrapping: true,
-                            keyMap: "sublime",
-                            foldGutter: true,
-                            gutters: ["CodeMirror-linenumbers", "CodeMirror-foldgutter"],
-                            extraKeys: {
-                                "Ctrl-Space": "autocomplete",
-                                "Ctrl-Q": function(cm){ cm.foldCode(cm.getCursor()); }
-                            }
+                    if (!monacoEditor) {
+                        require(['vs/editor/editor.main'], function() {
+                            monacoEditor = monaco.editor.create(monacoContainer, {
+                                value: rawOutput,
+                                language: 'html',
+                                theme: 'vs-dark',
+                                automaticLayout: true,
+                                formatOnPaste: true,
+                                formatOnType: true
+                            });
                         });
-                        // Fix for initially hidden textarea
-                        setTimeout(function() {
-                            cmEditor.refresh();
-                        }, 10);
                     } else {
-                        cmEditor.setValue(rawOutput);
-                        setTimeout(function() {
-                            cmEditor.refresh();
-                        }, 10);
-                    }
-                    
-                    // CodeMirror wrapper needs to be visible
-                    if(cmEditor.getWrapperElement()) {
-                        cmEditor.getWrapperElement().style.display = 'block';
+                        monacoEditor.setValue(rawOutput);
                     }
 
                     toggleBtn.innerHTML = '<i class="fas fa-paint-brush"></i> Use Visual Builder';
                 } else {
                     localStorage.setItem('snippetEditorMode', 'visual');
-                    // Get value from CodeMirror back to textarea and GrapesJS
-                    if (cmEditor) {
-                        textArea.value = cmEditor.getValue();
-                        cmEditor.getWrapperElement().style.display = 'none';
+                    if (monacoEditor) {
+                        textArea.value = monacoEditor.getValue();
                     }
+                    monacoContainer.style.display = 'none';
+                    
                     editor.setComponents(textArea.value);
-                    isGrapesJsModified = false; // Reset flag since we just synced
+                    isGrapesJsModified = false;
                     
                     textArea.style.display = 'none';
                     gjsWrap.style.display = 'block';
@@ -775,8 +738,8 @@
                         textArea.value = finalOutput;
                     }
                 } else {
-                    if (cmEditor) {
-                        textArea.value = cmEditor.getValue();
+                    if (monacoEditor) {
+                        textArea.value = monacoEditor.getValue();
                     }
                 }
             });
diff --git a/sisvietnamvn_main/src/main/resources/templates/manage/snippets/list.html b/sisvietnamvn_main/src/main/resources/templates/manage/snippets/list.html
index 4ce3b056..793bbabb 100644
--- a/sisvietnamvn_main/src/main/resources/templates/manage/snippets/list.html
+++ b/sisvietnamvn_main/src/main/resources/templates/manage/snippets/list.html
@@ -54,6 +54,12 @@
                                     <a th:href="@{/manage/snippets/{id}/edit(id=${snippet.id})}" class="btn btn-sm btn-outline-info mr-1" title="Edit">
                                         <i class="fas fa-edit"></i>
                                     </a>
+                                    <form th:action="@{/manage/snippets/{id}/duplicate(id=${snippet.id})}" method="post" style="display:inline;">
+                                        <input type="hidden" th:name="${_csrf.parameterName}" th:value="${_csrf.token}" />
+                                        <button type="submit" class="btn btn-sm btn-outline-warning mr-1" title="Duplicate">
+                                            <i class="fas fa-copy"></i>
+                                        </button>
+                                    </form>
                                     <form th:action="@{/manage/snippets/{id}/delete(id=${snippet.id})}" method="post" style="display:inline;" onsubmit="return confirm('Are you sure you want to delete this snippet?');">
                                         <input type="hidden" th:name="${_csrf.parameterName}" th:value="${_csrf.token}" />
                                         <button type="submit" class="btn btn-sm btn-outline-danger" title="Delete">