diff --git a/content-editable/index.html b/content-editable/index.html
index 4b5b8f2..570adee 100644
--- a/content-editable/index.html
+++ b/content-editable/index.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<li>
+<html>
 
 <head>
     <meta charset='utf-8'>
@@ -18,4 +18,6 @@
             <li> 3. Honey </li>
         </ul>
     </div>
-</body>
\ No newline at end of file
+</body>
+
+</html>
\ No newline at end of file
diff --git a/data-attribute/index.html b/data-attribute/index.html
index 8b6d869..e1a760c 100644
--- a/data-attribute/index.html
+++ b/data-attribute/index.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<li>
+<html>
 
 <head>
     <meta charset='utf-8'>
@@ -11,7 +11,7 @@
     <script>
         function reveal() {
             let dataDiv = document.getElementById('data-attr');
-            let value = dataDiv.getAttribute('data-custom-attr'); 
+            let value = dataDiv.getAttribute('data-custom-attr');
             document.getElementById('msg').innerHTML = `<mark>${value}</mark>`;
         }
 
@@ -21,11 +21,14 @@
 <body>
     <div class="demo">
         <h2> Know data attribute </h2>
-        <div class="data-attribute" id="data-attr" data-custom-attr="You are just Awesome!"> I have a hidden secret! </div>
+        <div class="data-attribute" id="data-attr" data-custom-attr="You are just Awesome!"> I have a hidden secret!
+        </div>
         <button onclick="reveal()">Reveal</button>
 
-        <br/>
-        
+        <br />
+
         <p id="msg"></p>
     </div>
-</body>
\ No newline at end of file
+</body>
+
+</html>
\ No newline at end of file
diff --git a/mark/index.html b/mark/index.html
index 9e8e5ad..ad385df 100644
--- a/mark/index.html
+++ b/mark/index.html
@@ -14,4 +14,5 @@
         <h1>Mark something to Highlight</h1>
         <p> Did you know, you can <mark>"Highlight something interesting"</mark> just with a HTML tag? </p>
     </div>
-</body>
\ No newline at end of file
+</body>
+</html>
\ No newline at end of file
diff --git a/output/index.html b/output/index.html
index c513965..60e578f 100644
--- a/output/index.html
+++ b/output/index.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<li>
+<html>
 
     <head>
         <meta charset='utf-8'>
@@ -18,4 +18,5 @@
                 = <output name="x" for="a b"></output>
             </form>
         </div>
-    </body>
\ No newline at end of file
+    </body>
+</html>
\ No newline at end of file
