Sometimes a little trick would be the key for the biggest solutions, In wistia there is an option called videofoam to create responsive video embed code, but unfortunately it is not yet available for playlist embed. In this blog I am going to show you a simple trick to get responsive wistia playlist in yours embeded sites in the following steps,
Choose anyone of your favourite theme while creating embed code, but if you choose BENTO theme, just enable the option to make playlist menu in the bottom of the video
see the scrrenshot
Add the following little css in your site's css file,
iframe.wistia_playlist {
max-width: 100%;
}
Seems to be little but I hope, it would help lot.