<!DOCTYPE html>
<html>
<head>
<title>Title of the document</title>
<style>
@keyframes blinking {
0% {
background-color: #06c3d1;
border: 3px solid #666;
}
100% {
background-color: #270da6;
border: 3px solid #666;
}
}
#blink {
width: 200px;
height: 200px;
animation: blinking 1s infinite;
}
</style>
</head>
<body>
<div id="blink"></div>
</body>
</html>