body {
  background: linear-gradient(270deg, #12201a, #0d1d1f, rgb(46, 29, 59));
  background-size: 400% 400%;
  font-family: 'Roboto', sans-serif;
  animation: BackgroundGradient 20s ease infinite;
}

@keyframes BackgroundGradient { 
    0%   { background-position: 0%   50% }
    50%  { background-position: 100% 51% }
    100% { background-position: 0%   50% }
}