如何修复此下拉移动菜单

Question

我遇到有关此移动视图下拉菜单的问题，当我单击“研究所”（具有子子菜单）时，它在桌面视图中默认情况下在左侧显示下拉菜单，而不是在底部显示移动菜单

它只是HTML CSS和Javascript。请帮助修复它。谢谢

        //This is the mail script from inside a switch:
case 'delete event':
        $eventCreator = get_event_creator($event_title, $event_id);
        $creatorName = $eventCreator['first_name'] . ' ' . 
        $eventCreator['last_name'];
        $event = retrieve_event(urldecode($event_title), $event_id);
        $list = retrieve_invitee_list($event_id);
        foreach ($list as $key => $value) {
            $mail->addAddress($value['email'], $value['first_name']);
        }
        $body .= '<h3>Event Cancellation</h3>';
        $body .= '<p style="margin-top:25px;">The event <strong>' . 
        $event_title . '</strong> created by ' . $creatorName . ' on ' . 
        $event['event_date'] . ' has been cancelled.</p>';
        $body .= '<p>To create and manage your own events, <a 
        href="localhost/InviteMe Application/landing_page.php">sign 
        up</a> to InviteMe.</p>';
        $body .= "</body></html>";
        $mail->Subject = "Event Cancellation";

        /*This is temporary as my xammp server seems not to be using an 
        up to date CA cert */
        $mail->SMTPOptions = array(
            'ssl' => array(
                'verify_peer' => false,
                'verify_peer_name' => false,
                'allow_self_signed' => true
            )
        );
        $mail->SMTPDebug = 3;
        $mail->Host = 'smtp.gmail.com';
        $mail->Port = 587;
        $mail->SMTPSecure = 'tls';
        $mail->SMTPAuth = true;
        $mail->Username = "invitemedemo@gmail.com";
        $mail->Password = "<password>";
        $mail->setFrom('invitemedemo@gmail.com', "InviteMe");
        $mail->Body = $body;
        $mail->isHTML(true);
        if (!$mail->send()) {
            echo 'Mailer Error: ' . $mail->ErrorInfo;
            return false;
        } else {
            return true;
        }