Please take a look and give me suggestions what to improve
Do you have a link for us?
yes of course! sorry
No problem 
It looks really good and it is responsive! Good job!
One little thing (a CodePen thing): You can add jQuery through the settings tab. Everything you put inside the HTML section is put inside body tags by CodePen. So you don’t need the head (you can set those in the settings) and the body (are added automatically) tags.
Thanks a lot for your advice! I finally figure out how CodePen works.