.loader {
  position: relative;
  display: block;
  margin: 0 auto;
  width: 50px;
  height: 50px;
  border: 2px solid #0cf;
  border-radius: 50%;

  animation: spin 0.75s infinite linear;
}
.loader::before,
.loader::after {
  left: -2px;
  top: -2px;
  display: none;
  position: absolute;
  content: '';
  width: inherit;
  height: inherit;
  border: inherit;
  border-radius: inherit;
}


/*
 * LOADER 1
 */
.loader-1 {
  border-top-width: 0;
}


/*
 * LOADER 2
 */
.loader-2 {
  border-top-color: transparent;
}
.loader-2::after {
  display: block;
  left: -2px;
  top: -2px;
  border: inherit;
  transform: rotate(65deg);
}


/*
 * LOADER 3
 */
.loader-3,
.loader-3::before,
.loader-3::after {
  display: inline-block;
  border-color: transparent;
  border-top-color: #0cf;
  animation-duration: 1.2s;
}
.loader-3::before {
  transform: rotate(120deg);
}
.loader-3::after {
  transform: rotate(240deg);
}

/*
 * LOADER 4
 */
.loader-4 {
  border-top-color: transparent;
}
.loader-4::after {
  display: block;
  border-color: transparent;
  border-top-color: #0cf;
  animation: spin 1.25s infinite linear reverse;
}


/*
 * LOADER 5
 */
.loader-5,
.loader-5::before {
  display: inline-block;
  border-color: transparent;
  border-top-color: #0cf;
}
.loader-5::before {
  animation: spin 1.5s infinite ease;
}


/*
 * LOADER 6
 */
.loader-6 {
  border-color: transparent;
  border-top-color: #0cf;
  animation-duration: 5s;
}
.loader-6::after {
  display: block;
  border-color: transparent;
  border-top-color: #0cf;
  animation: spin 0.75s infinite ease-in-out alternate;
}


@keyframes spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
}