PHP CSS解析器无法解析属性值中的分号

I'm using this function to parse the CSS files, but when it comes to property values containing semicolon, it breaks. Example:

#logo {
    background-image: url("data:image/png;base64,..................");
}

I changed the explode delimiter to " " but it didn't produce expected results. Please help.

Function:

function parse($file){
    $css = file_get_contents($file);
    preg_match_all( '/(?ims)([a-z0-9\s\.\:#_\-@,]+)\{([^\}]*)\}/', $css, $arr);
    $result = array();
    foreach ($arr[0] as $i => $x){
        $selector = trim($arr[1][$i]);
        $rules = explode(';', trim($arr[2][$i]));
        $rules_arr = array();
        foreach ($rules as $strRule){
            if (!empty($strRule)){
                $rule = explode(":", $strRule);
                $rules_arr[trim($rule[0])] = trim($rule[1]);
            }
        }

        $selectors = explode(',', trim($selector));
        foreach ($selectors as $strSel){
            $result[$strSel] = $rules_arr;
        }
    }
    return $result;
}

Execution:

$css = parse('content/custom.css');
echo print_r($css);

What about using a temporary place holder string for the offsensive ;base64, then do the split, then restore it back, something like:

Replace this line:

 $rules = explode(';', trim($arr[2][$i]));

with this:

//replace ;base64 with a placeholder
$placeholder=uniqid();
$arr[2][$i] = str_replace(";base64",$placeholder,$arr[2][$i]);
//explode
$rules = explode(';', trim($arr[2][$i]));
//restore from placeholder
$rules = array_map(function ($el) {
    return str_replace($placeholder, ";base64", $el);
}, $rules);