Something like this would do the job.
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>Untitled Document</title>
<style>
html, body {
margin:0;
padding:0;
height:100%;
}
.form {
display:flex;
height:100%;
height:100vh;
}
.updated{
margin:auto;
position:relative;
}
input{
width:30$;
height:30px;
line-height:30px;
border:1px solid #ccc;
}
#update {
background:red;
animation:fader 5s 3s forwards;
z-index:-1;
}
@keyframes fader{
from{background:red;}
to{background:#fff;}
}
</style>
</head>
<body>
<form class="form" name="form1" method="post" action="">
<div class="updated">
<label for="update">Enter Stuff : </label>
<input type="text" name="update" id="update">
</div>
</form>
</body>
</html>