<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Simple Calendar</title>
    <style>
        body {
            font-family: Arial, sans-serif;
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            background-color: #f0f2f5;
        }
        .calendar {
            max-width: 700px;
            margin: 50px auto;
            padding: 20px;
            background-color: white;
            border-radius: 8px;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
            text-align: center;
        }
        .calendar table {
            width: 100%;
            border-collapse: collapse;
        }
        .calendar th, .calendar td {
            padding: 10px;
            border: 1px solid #ddd;
        }
        .calendar th {
            background-color: #007bff;
            color: white;
        }
        .calendar td {
            text-align: center;
        }
        .calendar td:hover {
            background-color: #f1f1f1;
        }
    </style>
</head>
<body>
    <div class="calendar">
        <h1>Simple Calendar</h1>
        <table>
            <thead>
                <tr>
                    <th>Sun</th>
                    <th>Mon</th>
                    <th>Tue</th>
                    <th>Wed</th>
                    <th>Thu</th>
                    <th>Fri</th>
                    <th>Sat</th>
                </tr>
            </thead>
            <tbody>
                <tr>
                    <td></td>
                    <td></td>
                    <td></td>
                    <td>1</td>
                    <td>2</td>
                    <td>3</td>
                    <td>4</td>
                </tr>
                <tr>
                    <td>5</td>
                    <td>6</td>
                    <td>7</td>
                    <td>8</td>
                    <td>9</td>
                    <td>10</td>
                    <td>11</td>
                </tr>
                <tr>
                    <td>12</td>
                    <td>13</td>
                    <td>14</td>
                    <td>15</td>
                    <td>16</td>
                    <td>17</td>
                    <td>18</td>
                </tr>
                <tr>
                    <td>19</td>
                    <td>20</td>
                    <td>21</td>
                    <td>22</td>
                    <td>23</td>
                    <td>24</td>
                    <td>25</td>
                </tr>
                <tr>
                    <td>26</td>
                    <td>27</td>
                    <td>28</td>
                    <td>29</td>
                    <td>30</td>
                    <td>31</td>
                    <td></td>
                </tr>
            </tbody>
        </table>
    </div>
</body>
</html>