.rainbow {
    font-weight: 700;
    font-size: 3.6rem; /* adjust as needed */
    display: inline-block;
    background: linear-gradient(
        90deg,
        red,
        orange,
        yellow,
        lime,
        cyan,
        blue,
        violet,
        red
    );
    background-size: 600%;
    -webkit-background-clip: text;
    color: transparent;

    animation: rainbowSine 9s linear infinite;
}
/* Keyframes per l’animazione del gradiente */
@keyframes rainbowSine {
  0%   { background-position:   0% 50%; }
  50%  { background-position: 100% 50%; }
  100% { background-position:   0% 50%; }
}