<style>
input[type=text], input[type=email], input[type=number], input[type=date], input[type=tel], select, textarea {   
 width: 100%;  
 padding: 12px 12px;  
 margin: 8px 0;   
 box-sizing: border-box;
}

table, tbody, tr, td, label {
border-top:0;
border-bottom:0;
line-height: 8px;
}
</style>

<form id="form" action="contato/contatosite.php" method="post" name="form">
<table style="line-height: 12px;" border="0" width="100%" cellpadding="2" align="center">
<tbody>
<tr>
<td><label for="nome">Nome:</label>
<input id="nome" form="form" maxlength="100" name="nome" type="text" autofocus="" />
</td></tr>
<tr>
<td><label for="cel">Telefone:</label>
<input id="cel" maxlength="15" name="cel" type="text" placeholder="00 00000-0000" /></td>
</tr>
<tr>
<td><label for="email">Email:</label>
<input id="email" maxlength="100" multiple="multiple" name="email" type="email" /></td>
</tr>
<tr>
<td><label for="texture">Sua Mensagem:</label>
<textarea id="textarea" name="textarea"></textarea></td>
</tr>
<tr>
<td colspan="6" align="right"><button type="submit">Enviar</button></td>
</tr>
</tbody>
</table>
</form>