Microformats WordPress theme uses two worlds.
World 1. Fixed size layout.
World 2. A responsive technique of scaling to fit the browser width when the browser width is less than 800px.
The main theme idea is to support Article microformats for your posts.
You can test the article microformats from the Google structure testing tool. Use this URL https://programming-review.com/find-grep/ for example to test.
Since it is based on the Underscores theme, it has all the good practices and solid features foundation. It supports custom site icon, custom header, and custom background image as well as other themes specific items.
Microformats theme at a top supports 500+ Google fonts and custom colors.
It doesn’t show the header part once you are visiting posts. This should focus your visitors on the post content.