*{box-sizing:border-box;margin:0;padding:0}a{color:inherit;text-decoration:none}.card{position:relative}.card-button{background-color:#007bff;border:none;border-radius:4px;color:#fff;cursor:pointer;padding:5px 10px;position:absolute;right:0;top:0}#container{margin:0 auto}#container,#video{height:375px;width:500px}#video{background-color:#666;border-radius:15px}.hidden{display:none}#btn{border-radius:10px;display:block;height:50px;margin:15px auto;width:150px}#btn:hover{cursor:pointer}