.customervedios {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%; 
    margin: 0 auto 15px;
    background-color: black;
}

.customervedios iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: 0;
}

@media (max-width: 576px) {
    .customervedios {
        max-width: 100%; 
    }
}