Animation

This line: animation: moveit 2s alternate infinite; is shorthand for these four lines: animation-name: moveit;
animation-duration: 2s;
animation-iteration-count: infinite;
animation-direction: alternate;


But let's try a more involved animation:

by changing your @keyframes: #inside {
position: absolute;
top: 0;
left: 0;
height: 10px;
width: 10px;
background: red;
animation: moveit 2s alternate infinite
}

@keyframes moveit {
25% {top: 190px; left: 0}
50% {top: 0px; left: 95px}
75% {top: 190px; left: 190px}
100% {top: 0px; left: 190px;}
}