HTMLify

* {
  margin: 0;
  padding: 0;
}
body {
  background-color: #141414;
  inset: 0;
  height: 100vh;
  display: flex;
  place-content: center;
  align-items: center;
  overflow: hidden;
}

.gradient {
  --size: 40vw;

  width: var(--size);
  height: var(--size);
  filter: blur(calc(var(--size) / 5));
  background-image: linear-gradient(#e63946, #1d3557);
  animation: rotate 20s cubic-bezier(1, 0.2, 0.2, 1) alternate infinite;
  border-radius: 30% 70% 70% 30% / 30% 30% 70% 70%;
  transition: all 0.25s ease-out;
}

.noise {
  position: absolute;
  height: 100%;
  width: 100%;
  background-image: url(https://raw.githubusercontent.com/taimoorshahzada/Film-Grain-Noise-Effect-on-Background-in-Website-using-Pure-CSS/main/noise.gif);
  opacity: 0.02;
  pointer-events: none;
  z-index: 1000;
}

@keyframes rotate {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}