body {
            font-family: Arial, sans-serif;
            background-color: #f4f4f4;
            margin: 0;
            padding: 20px;
        }

        h1 {
            text-align: center;
            color: #333;
        }

        form, .controls, .stamps {
            max-width: 600px;
            margin: 20px auto;
            background: white;
            padding: 20px;
            border-radius: 8px;
            box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
        }

        label {
            font-weight: bold;
        }

        input[type="text"], input[type="number"], select {
            width: 100%;
            padding: 8px;
            margin: 10px 0;
            border-radius: 4px;
            border: 1px solid #ccc;
        }

        button {
            padding: 10px 20px;
            background-color: #28a745;
            color: white;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            margin-top: 10px;
        }

        button:hover {
            background-color: #218838;
        }

        .controls button {
            background-color: #007bff;
        }

        .controls button:hover {
            background-color: #0056b3;
        }

        #stampDisplay {
            margin-top: 20px;
            font-size: 1.1em;
        }

        #untradedStamps {
            margin-top: 20px;
            font-size: 1.1em;
            color: #dc3545;
        }