body{text-align: center;padding: 150px;}
h1{position: fixed;top: 20%;left: 50%;transform: translate(-50%, -50%);font-size: 50px;}
body{font-family: sans-serif;}
.firma{
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 10px; 
    padding-top: 60vh;
}