Update html_helper.py

html_helper.py

@@ -96,5 +96,7 @@ def create_html_from_midi(midifile):
 
 def create_html_youtube_player(youtube_url):
     youtube_url = to_youtube_embed_url(youtube_url)
-    html = f"""<iframe width="560" height="315" src='{youtube_url}' title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>"""
-    return html
+    html = f"""<div style="display: flex; justify-content: center; align-items: center;">
+                  <iframe width="560" height="315" src='{youtube_url}' title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
+              </div>"""
+    return html