body {
            font-family: Arial, sans-serif;
            margin: 0;
            padding: 0;
        }
        
        header {
            background-color: #f5f5f5;
            padding: 10px;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        header img.avatar {
            width: 150px;
            height: 150:px;
            border-radius: 5%;
        }
        
        .square-button {
            background-color: #ccc;
            color: #fff;
            border: none;
            padding: 10px 20px;
            border-radius: 4px;
            font-weight: bold;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
            cursor: pointer;
        }
        
        footer {
            background-color: #f5f5f5;
            padding: 10px;
            text-align: center;
        }
        
        .content {
            padding: 20px;
            }