Excelente clase de tablas!!!

CODIGO HTML

 <table>
                <thead>
                    <tr>
                        <th>Dias</th>
                        <th>Horario</th>
                    </tr> 
                </thead>

                <tbody>
                    <tr>
                        <td>Lunes</td>
                        <td>08~20 hs</td>
                    </tr>
                    <tr>
                        <td>Miercoles</td>
                        <td>08~20 hs</td>
                    </tr>
                    <tr>
                        <td>Viernes</td>
                        <td>08~20 hs</td>
                    </tr>
                </tbody>

            </table>

            CODIGO CSS
            table{
    margin: 40px 40px;

}

thead{
    background: #555555;
    color: white;
    font-weight: bold;
}
td,th{
    border: 1px solid #000000;
    padding: 8px 15px;
}