Already did, but he told me it's not possible atm :/Contact Yetishare since they claim everything is responsive as-is.
It's possible. Take a look at this for example
Code:https://mp4.moe/8621de14f20b24d0
Embeded: https://aho.moe/koe-de-oshigoto-the-animation/episode/2/
Just edit /plugins/mediaplayer/site/_embed.php with similar css, like the player element having 100% width, and more importantly, remove the width/height attributes of the <iframe> tag of the embed code.