.pb{
animation:pb 2s linear infinite;
}

@keyframes pb{
from {transform:translateX(-50%) translateY(-50%) rotate(0deg);}
to {transform:translateX(-50%) translateY(-50%) rotate(360deg);}
}

@-moz-keyframes pb{
from {transform:translateX(-50%) translateY(-50%) rotate(0deg);}
to {transform:translateX(-50%) translateY(-50%) rotate(360deg);}
}

@-webkit-keyframes pb{
from {transform:translateX(-50%) translateY(-50%) rotate(0deg);}
to {transform:translateX(-50%) translateY(-50%) rotate(360deg);}
}