Video Mobile Responsive [Broadcast theme]

[lbmedia1]

Hey!

I'm struggling to get my hero videos to be mobile responsive.  The video is cut off on the sides. 

I was trying different width and height with css,  but it's not working for me!
@media only screen and (max-width: 749px) {.section-video {width: 100%;
height: 100%;}} 
etc.

Any suggestions!

https://scarlett-grae.myshopify.com/
pswrd: ohneiz