html,
 body {
     margin: 0;
     padding: 0;
     width: 100vw;
     height: 100vh;
     background: #000;
     display: flex;
     justify-content: center;
     align-items: center;
 }

 video {
     object-fit: contain;
     width: 99.99%;
     height: 99.99%;
     background-color: #000;
 }