<!DOCTYPE html>
<html>
<head>
<style>
label {
display: block;
background: #dbdbd9;
width: 80px;
height: 80px;
}
#box:checked + label {
background: #fffc47;
color: #666666;
}
</style>
</head>
<body>
<form action="/form/submit" method="post">
<input type="checkbox" id="box" />
<label for="box">Click here</label>
</form>
</body>
</html>