How to include a PHP object in CSS?

When using an external stylesheet, is it possible to use a PHP object within CSS - without creating another object?

I have found workarounds with internal and inline CSS (e.g. How to include PHP code in CSS?) Below is some minimal code to show the problem and the workarounds I have found thus far.

in MyClass.php:

class MyClass{
    public $color = "blue";
}

in PHP/HTML file:

<?php
include_once('MyClass.php');
$myClass = new MyClass();
?>

... (in head - internal CSS workaround):

<style type="text/css">
    h1{color: <?php echo $myClass->color;?>;} 
</style>

... (in head - external CSS workaround):

  <link rel="stylesheet"  href="external.css") />

... (in body):

<h1> 1. Internal </h1>
<h2 style="color:<?php echo $myClass->color;?>"> 2. Inline </h2>
<h3> 3. External </h3>

In external.css [here is the "problem" - I need to create a new object]:

<?php
    header('Content-type: text/css');
    include('myClass.php');
    $myClass = new MyClass(); //<--ANOTHER OBJECT
?>
h3 {
    color: <?=$myClass->color?>;
}