Hello,

Please try to add this code into your custom css box:

@media (max-width: 979px){
.html5-video-player {
    width: 32%;
    height: 36%;}
}

If the issue persists, send us your wp credentials in a private reply. So we can give it a closer look.
-Add this code into your custom css box:

@media (max-width: 979px){
nav {  display: none;}
.mobile_small_menu {
    display: block;
    left: 10%;
}
#logo { margin-left: 43%;}
}

Let us know.

Best regards!

Hello,

1-I see the video is fitting the iPhone 5 screen size(screenshot) So is in iPad(screenshot) What is the issue?

2-Add this code into your custom css box:

@media (max-width: 1190px){
nav { display: none;}
.mobile_small_menu {  display: block;}
#logo { margin-left: 50% !important;}
}

Did you remove the page header title? The code above will make the mobile menu display until the header is wide enough for the menu to fit in, without needing to slip down and overwrite page header title.

Best regards!