[diimdeep]

Markdown files + Sublime MarkdownEditing plugin

[c-smile]

Or my html-notepad (https://html-notepad.com) if you prefer to use better WYSIWYG. Markdown is "a poor man WYSIWIG" anyway.

Especially if you need tables there or paste images from clipboard.

Or just use https://notes.sciter.com application. It stores document tree (db) locally: https://github.com/c-smile/sciter-sdk/blob/master/notes/res/...