Animation CSS

html, body {
  height: 100%;
}

body {
  background: -webkit-linear-gradient(0deg, #3f3f3f 10%, #202020 90%);
  background: linear-gradient(90deg, #3f3f3f 10%, #202020 90%);
  overflow: hidden;
}

.loader {
  height: 40px;
  width: 40px;
  position: absolute;
  left: 50%;
  margin-left: -20px;
  top: 50%;
  margin-top: -20px;
}

.loader:before,
.loader:after {
  content: "";
  height: 40px;
  width: 40px;
  border: 8px solid rgba(255,255,255,.5);
  border-radius: 10px;
  position: absolute;
  top: 0;
}

.loader:before {
  -webkit-animation: animate 2s infinite linear;
          animation: animate 2s infinite linear;
}

@-webkit-keyframes animate {
  0% {
    -webkit-transform: rotate(0) skew(0);
            transform: rotate(0) skew(0);
  }

  100% {
    -webkit-transform: rotate(180deg) skew(360deg);
            transform: rotate(180deg) skew(360deg);
  }
}

@keyframes animate {
  0% {
    -webkit-transform: rotate(0) skew(0);
            transform: rotate(0) skew(0);
  }

  100% {
    -webkit-transform: rotate(180deg) skew(360deg);
            transform: rotate(180deg) skew(360deg);
  }
}



.loader:after {
  -webkit-animation: animate2 2s infinite linear;
          animation: animate2 2s infinite linear;
}

@-webkit-keyframes animate2 {
  0% {
    -webkit-transform: rotate(0) skew(0);
            transform: rotate(0) skew(0);
  }

  100% {
    -webkit-transform: rotate(-180deg) skew(-360deg);
            transform: rotate(-180deg) skew(-360deg);
  }
}

@keyframes animate2 {
  0% {
    -webkit-transform: rotate(0) skew(0);
            transform: rotate(0) skew(0);
  }

  100% {
    -webkit-transform: rotate(-180deg) skew(-360deg);
            transform: rotate(-180deg) skew(-360deg);
  }
}