Steps to Reproduce:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
.test {
color: #fff;
}
<?php
echo $css;
?>
</style>
</head>
<body>
</body>
</html>
$css; the highlight of CSS expands to the end of the file.
Reproduces without extensions: Yes
Most helpful comment
PHP in