Wavy lines

@grid: 10x1 / 600px / #18173a
  * -17deg ~0 2% ^40% 
  | @svg-filter(.03, 12);

@place: center;
@size: 100%;

--colors: #f5fac8,#a5f0e4,#82c7eb,#8ea1f0;

:after {
  content: '';
  @size: 100%;
  background: @m50(
    linear-gradient(90deg, @p(--colors), transparent)
    @r(100%) @r(100%) / @r(2%, 60%) @r(.05vmin, 1vmin)
    no-repeat
  );
  animation: move @r(5s, 10s) -@r(50s) linear infinite;
}

@keyframes move {
  from { transform: translateX(100%); }
  to { transform: translateX(-100%); }
}