To elaborate on my comment: SyntaxError: Invalid or unexpected token is not an error that you will ever see related to CSS. This is a JavaScript error that occurs when there’s a syntax error in some JavaScript. If you see this error and it’s occurring in a CSS file, then it means that you have improperly loaded a CSS file in <script> tag, which means the browser will try to parse the CSS as JavaScript, which will inevitably produce a syntax error, because CSS is not valid JavaScript.
This will happen in WordPress if you try to use wp_enqueue_script() on a CSS file. Make sure you only use wp_enqueue_script() for JavaScript files, and wp_enqueue_style() for CSS files.