<div class="tilty">
tilting
</div>
.tilty {
text-align: center;
font-size:2em;
animation: tilt 1s infinite alternate;
}

@keyframes tilt {
from { transform: rotate(5deg); }
to { transform: rotate(-5deg); }
}

@-webkit-keyframes tilt {
from { transform: rotate(5deg); }
to { transform: rotate(-5deg); }
}