.vid li{
    position: relative;
}

.vid li::before{
    
    position: absolute;
    content: "Play";
    font-family: "Arial";
    font-size: 1em;
    color:white;
    text-align: center;
    width: 46px;
    line-height: 46px;
    background: rgba(0, 0, 0, .7);
    top:50%;
    margin-top: -23px;
    left:50%;
    margin-left: -23px;
    border-radius: 100%;
    z-index: 1;
}