Shimmering Focus - using the compact file bar appearance in different theme

[1AshenPage1]

I would like to ask if there is a way to find and use the code that made the file bar smaller and more compact. it looks much better than in normal theme of Obsidian or any other really and I love how compact it is, but I am used to another theme and am wondering if there is a way how to use this function in other themes?

If it is possible, could you please refer to me how to do it, or even share the code for it?

Thank you for any answer.