Put this on obs Custom CSS field on the browser source of the chat. URL used, replace CHANNEL: https://www.giambaj.it/twitch/jchat/v2/?channel=CHANNEL&hide_commands=true&hide_badges=true&size=3&font=2&stroke=2&shadow=1

j.css

/* Transparent background and fade in animation */

body {
     background-color: rgba(0, 0, 0, 0);
     margin: 0px auto;
     overflow: hidden;
}

 .chat_line {
     animation: fadeInRight 0.3s ease forwards;
}

 @keyframes fadeInRight {
     0% {
         opacity: 0;
         -webkit-transform: translate3d(100%, 0, 0);
         transform: translate3d(100%, 0, 0);
    }
     to {
         opacity: 1;
         -webkit-transform: none;
         transform: none;
    }
}