<table>
                <thead>
                    <tr>
                        <th>Dia</th>
                        <th>Horário</th>
                    </tr>
                </thead>
                <tbody>
                    <tr>
                        <td>Segunda</td>
                        <td>08h-20h</td>
                    </tr>
                    <tr>
                        <td>Quarta</td>
                        <td>08h-20h</td>
                    </tr>
                    <tr>
                        <td>Sexta</td>
                        <td>08h-20h</td>
                    </tr>
                </tbody>
            </table>    

table{
    margin:20px 0 40px;
}

thead{
    background: #555555;
    color: white;
    font-weight: bold;
}

td, th{
    border: 1px solid;
    color: #000000;
    padding: 8px 15px;
}