Php 电子邮件发送成功后在公共功能上添加css样式

我正在使用YITH请求报价，我想在发送电子邮件后更改CSS样式。 原公共职能如下：

public function trigger( $args ) {
        $this->raq                = $args;
        $this->raq['raq_content'] = YITH_Request_Quote()->get_raq_return();

        $recipients = (array) $this->get_recipient();

        if( $this->enable_cc ){
            $recipients[] =  $this->raq['user_email'];
        }

        $recipients = implode(',',$recipients);

        $return = $this->send( $recipients, $this->get_subject(), $this->get_content(), $this->get_headers(), $this->get_attachments() );

        if ( $return ) {
            YITH_Request_Quote()->clear_raq_list();
            yith_ywraq_add_notice( __('Your request has been sent successfully','yith-woocommerce-request-a-quote'), 'success' );
        }else {
            yith_ywraq_add_notice( __( 'There was a problem in sending your request. Please try again.', 'yith-woocommerce-request-a-quote' ), 'error' );
        }
    }

我试图补充：

    if ( $return ) {
       YITH_Request_Quote()->clear_raq_list();
?>
      <style>.raq-message {display:none !important;}</style>
<?php
      yith_ywraq_add_notice( __('Your request has been sent successfully','yith-woocommerce-request-a-quote'), 'success' );

if（$return）{
YITH_Request_Quote（）->clear_raq_list（）；
?>
.raq消息{显示：无！重要；}
根据调用
trigger
函数的位置，可能需要将样式添加到挂钩中：

if( $return ){
    YITH_Request_Quote()->clear_raq_list();

    // Add style to a header hook, like `wp_head` or `wp_print_styles`
    add_action( 'wp_head', function(){
        echo '<style>.raq-message { display: none !important; }</style>';
    });

    yith_ywraq_add_notice( __('Your request has been sent successfully','yith-woocommerce-request-a-quote'), 'success' );
} else {
    yith_ywraq_add_notice( __( 'There was a problem in sending your request. Please try again.', 'yith-woocommerce-request-a-quote' ), 'error' );
}

if（$return）{
YITH_Request_Quote（）->clear_raq_list（）；
//将样式添加到标题挂钩，如'wp_head'或'wp_print_styles'`
添加行动（'wp_head'，函数（）{
echo'.raq消息{显示：无！重要；}'；
});
yith_ywraq_添加_通知（“您的请求已成功发送”、“yith-woocommerce-request-a-quote”）、“成功”）；
}否则{
yith_ywraq_添加_通知（uuuu（“发送您的请求时出现问题，请重试”）、“yith-WOOMerce-request-a-quote”）、“错误”）；
}
Hi@Xhynk谢谢你的建议，但这不起作用。