body {
  background-image:
    /* top-left */
    radial-gradient(
      circle 2000px at top left,
      rgba(255,0,120,0.6) 0%,
      rgba(255,0,120,0) 70%
    ),
    /* top-right */
    radial-gradient(
      circle 2000px at top right,
      rgba(0,200,255,0.6) 0%,
      rgba(0,200,255,0) 70%
    ),
    /* bottom-right */
    radial-gradient(
      circle 2000px at bottom right,
      rgba(0,255,100,0.6) 0%,
      rgba(0,255,100,0) 70%
    ),
    /* bottom-left */
    radial-gradient(
      circle 2000px at bottom left,
      rgba(255,200,0,0.6) 0%,
      rgba(255,200,0,0) 70%
    );

  background-repeat: no-repeat;
}