$splitter = new \CssSplitter\Splitter();
// Load your css file
$css = file_get_contents('styles.css');

// Skip the first part as the Internet Explorer interprets your css until it reaches the limit
$selector_count = $splitter->countSelectors($css) - 4095;
// Calculate how many additional parts we need to create
$additional_part_count =  ceil($selector_count / 4095);

if($additional_part_count > 0) {
    // Loop and create the additional parts
    // Add an offset of two as we are creating the css from the second part on
    for($part = 2; $part < $additional_part_count + 2; $part++) {
        // Create or update the css files
        file_put_contents('styles_'. $part .'.css', $splitter->split($css, $part));
    }
}