Add Pagebar Effect in WordPress Template

The pagination function of WordPress templates is not very good, it only shows "previous page" or "next page", which feels quite monotonous. It would be better if we could add a page number effect. This can certainly be achieved through the plugin Pagebar. However, for us bloggers who are not building standalone websites, either we cannot request the blog service provider to add such plugins, or even if the blog service provider has added this plugin, there's no way for us to modify it, and these issues are always headache-inducing. So, let's get to the point - let's directly add this effect into the template!