<!DOCTYPE html>
<html>
<head>
    <style>
        .box {
            margin: 50px;
            height: 150px;
            width: 150px;
        }

        .shadow {
            margin: 20px;
            height: 300px;
            width: 300px;
            background-color: silver;
            border: 1px solid black;
            filter: drop-shadow(10px 10px 10px blue);
        }
    </style>
</head>

<body>

    <div class="shadow">
    </div>

</body>
</html>