Quick-add in codepen uses Bootstrap 4.
Use these links instead:
https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css
https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js
Also,
Quick-add in codepen uses Bootstrap 4.
Use these links instead:
https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css
https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js
Also,