How to integrate different stylesheets into a website?

There are three ways to include CSS in HTML or XHTML: linked, embedded, and inline. Instead of being included in the HTML page itself, the linked technique stores the CSS in a separate file. The header area of the HTML page houses the CSS when using the embedded technique.

You can simply use the new CSS in your site after creating a new CSS file and centralising everything with the @import function. To combine all of your CSS files into one file, use webpack. After that, "link" it into the website. I just added them as external CSS links and gave them names.