當我嘗試使用 PHPMailer 庫發送 HTML 電子郵件時，收到的電子郵件顯示不正確。我已經嘗試過使用不同的郵件客戶端（Gmail 和 Outlook），但它們看起來非常相似。這是我當前的代碼require_once 'includes/mail-denied.php'; // Here is specified the $message variable, containing the HTML and CSS (https://i.imgur.com/UG1B34V.png)$keys = array('{{ server_name }}', '{{ player_name }}', '{{ reason_area }}', '{{ date }}');$_POST['description'] = nl2br($_POST['description']);$replace = array($servernam, $name, $_POST['description'], date("Y"));$message = str_replace($keys, $replace, $message);$mail_manager = new PHPMailer(true);try {    $mail_manager->SMTPDebug = 2;    $mail_manager->setFrom('noreply@'.$_SERVER['HTTP_HOST'], $servernam);    $mail_manager->addAddress($mail);    $mail_manager->addReplyTo('noreply@'.$_SERVER['HTTP_HOST'], 'Do not reply');    $mail_manager->isHTML(true);    $mail_manager->Subject = "Staff Application System - ".$servernam;    $mail_manager->Body    = $message;    $mail_manager->AltBody = 'Your application has been declined.';    $mail_manager->send();} catch (Exception $e) {    echo "Message could not be sent. Mailer Error: {$mail_manager->ErrorInfo}";我確實收到了電子郵件，但部分 HTML 看起來很亂。這是 HTML 代碼：<?php$message = '<div style="width: 500px;    height: 110px;    position: fixed;    background-color: #ff9999;    border-bottom: 1px solid #ff8080;    display: block;    border-top-left-radius: .5em;    border-top-right-radius: .5em;    color: #FFF;    text-align: center;    font-family: \'Product Sans\', Arial, sans-serif;">    <h2>Staff System Application</h2>    <h3>{{ server_name }}</h3></div>它應該是這樣的： 這就是我收到電子郵件時的樣子： 我對電子郵件中的 HTML 很陌生，我不知道如何解決這個問題。