Непрерывное движение элемента влево-вправо

.haeder-fly {
    animation-direction: alternate;
	animation-duration: 5s;
	animation-name: move;
	animation-iteration-count: infinite;
	animation-timing-function: linear;

}
@keyframes move {
from {
	margin-left: 0;
}
to {
	margin-left: 40px;
}
}