To improve SEO and eliminate duplicate content, you should ensure that the text and HTML of your web pages are unique. Avoid using the same content across multiple pages, as this can negatively impact your search engine rankings. Focus on creating original and high-quality content that is relevant to your target audience. In addition, remove any unnecessary or duplicate CSS class styles that might exist in your HTML. While CSS classes themselves don’t directly cause duplicate content issues, multiple instances of identical classes with the same styling can increase file size and impact site speed. Stripping out such unnecessary styles improves page load time which is a ranking factor. The key is unique content, and efficiently optimized site code.