<div class="content <?php echo ($page['sidebar'])?"col-sm-9":"col-sm-12"?>"></div>
$phone = $_POST['phone'];
$subject = "Тема";
$headers = "Content-Type: text/html; charset=UTF-8\r\n";
$message = "Текст письма";
$to = "mail@mail.ru";
$res = mail($to, $subject, $message, $headers );
<div class="box">
<div id="test">
<div></div>
</div>
</div>
.box div:hover