It's based in Hyde, which is a Jekyll theme that pairs a prominent sidebar with uncomplicated content. It's based on Poole, the Jekyll butler.
Ubuntu:
sudo apt install ruby-dev
sudo gem install jekyll jekyll-gist jekyll-sitemap jekyll-seo-tag jekyll-gist jekyll-paginate
For the rest: check the Hyde docs.
Franco Peschiera
Open sourced under the MIT license.