source/font-awesome/less/spinning.less

// Spinning Icons
// --------------------------

.@{fa-css-prefix}-spin {
  -webkit-animation: spin 2s infinite linear;
  -moz-animation: spin 2s infinite linear;
  -o-animation: spin 2s infinite linear;
  animation: spin 2s infinite linear;
}

@-moz-keyframes spin {
  0% { -moz-transform: rotate(0deg); }
  100% { -moz-transform: rotate(359deg); }
}
@-webkit-keyframes spin {
  0% { -webkit-transform: rotate(0deg); }
  100% { -webkit-transform: rotate(359deg); }
}
@-o-keyframes spin {
  0% { -o-transform: rotate(0deg); }
  100% { -o-transform: rotate(359deg); }
}
@-ms-keyframes spin {
  0% { -ms-transform: rotate(0deg); }
  100% { -ms-transform: rotate(359deg); }
}
@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(359deg); }
}