A) questa è la parte css dove sta #fullscreen-bg__video:

codice:
body {
margin: 0;
padding: 0;
}


.content {
margin: 0 auto;
width: 100%;
max-width: 960px;
padding: 0 15px;
}


h1 {
margin: 60px 0;
padding: 0;
font-size: 50px;
text-align: center;
}


p {
margin: 0 0 30px 0;
font-size: 30px;
line-height: 1.5;
}


.fullscreen-bg {
position: fixed;
top: 0;
right: 0;
bottom: 0;
left: 0;
overflow: hidden;
z-index: -100;
}


.fullscreen-bg__video {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
}


@media (min-aspect-ratio: 16/9) {
.fullscreen-bg__video {
height: 300%;
top: -100%;
}
}


@media (max-aspect-ratio: 16/9) {
.fullscreen-bg__video {
width: 300%;
left: -100%;
}
}


@media (max-width: 767px) {
.fullscreen-bg {
background: url('../img/videoframe.jpg') center center / cover no-repeat;
}


.fullscreen-bg__video {
display: none;
}
}
C)ended non so cosa sia, ho trovato questo script in questa pagina internet e speravo funzionasse: http://stackoverflow.com/questions/1...ect-after-play