cdnjs is a free distributed JS library delivery service.
Cloudflare is a web-infrastructure and website-security company, providing content-delivery-network services, DDoS mitigation, Internet security, and distributed domain-name-server services.
Font Awesome is a font and icon toolkit based on CSS and Less.
HTTP/3 is the third major version of the Hypertext Transfer Protocol used to exchange information on the World Wide Web.
Paddle is a billing and payment gateway for B2B SaaS companies.
Phusion Passenger is a free web server and application server with support for Ruby, Python and Node.js.
Prism is an extensible syntax highlighter.
Ruby on Rails is a server-side web application framework written in Ruby under the MIT License.
A modest JavaScript framework for the HTML you already have.