在PHP变量或DOMDocument中更改CSS元素

I'm building emails from external variables of CSS and HTML and then combining them as inline styles. Before they are combined, however, I want to alter the CSS.

In the below, I want to remove the padding and margin from the body. How should I do this - preg_match or is there something "cleaner"?

$css = "body {
         background: #fff;
         color: #000;
         padding: 0;
         margin: 0;
         font: 83%/1.4 verdana,sans-serif;
         -webkit-text-size-adjust: 100%;
         -ms-text-size-adjust: 100%;
     }

     a, a:link, a:visited, a:hover, a:active {
         background: transparent;
         text-decoration: none;
         cursor: pointer;
     }";

Also, it's well worth mentioning that I am getting the CSS (then inline-styling) like this with the below so maybe the DOMDocument can help me - that seems cleaner, but I don't know where to start.

    use TijsVerkoyen\CssToInlineStyles\CssToInlineStyles;

    $dom = new DOMDocument();
    @$dom->loadHTML($row['htmlbody']); //from a database
    $cssobj = $dom->getElementsByTagName('style');
    $bodyobj = $dom->getElementsByTagName('body')->item(0);
    $plainbody = new DOMDocument();
    foreach ($bodyobj->childNodes as $child){
        $plainbody->appendChild($plainbody->importNode($child, true));
    }
    $body = $plainbody->saveHTML();
    $css = $cssobj->item(0)->nodeValue;
    $cssToInlineStyles = new CssToInlineStyles();
    $originalemail = $cssToInlineStyles->convert(
        $body,
        $css
    );

If you know the exact text that you want to remove, you can use a str_replace() from php. Example: $str_replace('margin:0;','',$css)

or

$str = preg_replace('/margin:(.*?);/', '', $css)