Hey,

Sorry for the slow reply, I was travelling all day yesterday and have just setup internet in my hotel.

Yes, Microthemer adds new CSS styles that override the existing ones, rather than replacing them. So it does add extra bytes of code to the site. If we're approaching this from a purely technical angle, those extra bytes of CSS code will increase download time by a negligible (albeit non-zero) amount. The reason I didn't answer your previous question from that perspective is that it's not normally what people are asking when say "will this slow my site down". Normally, that comes from experience with themes and plugins that produce a noticeable lag on the site's performance after installation. Microthemer doesn't produce that. The extra bytes of CSS you add can be considered in the same way as extra bytes of HTML when you add an extra paragraph of text to a blog post. If it's worth saying, you're unlikely to omit it on the grounds of page speed optimisation. Furthermore, Microthemer allows you to load CSS for "below the fold" content asynchronously, which doesn't block the loading of priority content like text, images, and critical CSS (for initially rendering the page).

In answer to your question about Gutenberg blocks, by default Microthemer sorts your styles into page-specific folders. But you can alter the targeting of folders to make them global or apply to a certain type of page, or an arbitrary sub-set of pages. So yes, you can certainly apply styles that will affect all buttons across the site when using Gutenberg or a page builder. You can learn more about folder targeting options here:

https://themeover.com/load-wordpress-css-on-specific-pages/

I hope that helps. Let me know if you have any more questions.

Thanks,
Sebastian

P.S. I'm currently working on deep integration with Gutenberg and Full Site Editing (FSE). This will make is possible (and advisable) to style Gutenberg blocks by loading the editor view inside Microthemer, rather than the frontend view.

P.P.S I'm on holiday until Jan 16th, so I'll be a bit patchy on my replies until then, but will still aim to get back to you within 24 hours.