Build your personal knowledge base with Trilium Notes
Trilium Notes is a hierarchical note taking application with focus on building large personal knowledge bases. See screenshots for quick overview:

Trilium is provided as either desktop application (Linux, Windows, Mac) or web application hosted on your server (Linux).
trilium executable.See wiki for complete list of documentation pages.
You can also read Patterns of personal knowledge base to get some inspiration on how you might use Trilium.
Use a browser based dev environment
Or clone locally and run
npm install
npm run start