<div class="loader"></div>
.loader {
  --s: 150px; /* adjust this to control the size */
  
  --_d: calc(0.353*var(--s));/* 0.353 = sin(45deg)/2 */
  width: calc(var(--s) + var(--_d)); 
  aspect-ratio: 1;
  display: flex;
  margin: calc(var(--s)/3) 0;
}
.loader:before,
.loader:after {
  content: "";
  flex: 1;
  clip-path: polygon(var(--_d) 0,100% 0,100% calc(100% - var(--_d)),calc(100% - var(--_d)) 100%,0 100%,0 var(--_d));
  background:
    conic-gradient(from -90deg at calc(100% - var(--_d)) var(--_d),
     #fff 135deg,#666 0 270deg,#aaa 0);
  animation: load 1.5s infinite cubic-bezier(0,.5,.5,1.8) alternate;
}
.loader:before {
  margin-right: calc(var(--_d)/-2 - 1px);
}
.loader:after {
  margin-left: calc(var(--_d)/-2 - 1px);
  animation-delay: -.75s
}
@keyframes load{
  0%,40%   {transform:translateY(calc(var(--s)/-4))}
  60%,100% {transform:translateY(calc(var(--s)/4))}
}


body {
  margin: 0;
  height: 100vh;
  display: grid;
  place-content: center;
  background: #000;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.