Demo corner

<!DOCTYPE html>
<html>
<head>
    <title>Demo corner</title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<style type="text/css">
#page{
position: relative;
margin-top: 30px;
margin-left: 30px;
background: #6F0020;
width: 200px;
height: 100px;
padding:10px;
overflow: hidden;
}

.corner1, .corner2, .corner3, .corner4{
width: 26px;
height: 26px;
background: white;
-moz-border-radius: 13px;
-webkit-border-radius: 13px;
border-radius: 13px;
}

.corner1{
position: absolute;
top: -13px;
left: -13px;
}

.corner2{
position: absolute;
top: -13px;
right: -13px;
}

.corner3{
position: absolute;
bottom: -13px;
right: -13px;
}

.corner4{
position: absolute;
bottom: -13px;
left: -13px;
}

</style>
</head>

<body>
<div id="page">
<span class="corner1"></span><span class="corner2"></span><span class="corner3"></span><span class="corner4"></span>
Test Test Test Test Test Test Test Test Test Test Test Test Test Test Test
</div>

</body>
</html>