Currently working on a web application using Spring Boot and Thymeleaf as the template engine. I've stored all my CSS files in the "resource/static/css" directory. However, when attempting to edit an HTML file, STS does not provide suggestions for CSS classes from either my custom CSS file or the Bootstrap CSS file. I've tried adjusting various settings such as enabling code suggestions in preferences and adding code proposals in editors, but unfortunately, nothing seems to be working.