md++
A lightweight Markdown reader for Windows and macOS that opens a .md file on double-click, with a built-in file-watch mode that highlights and steps through external changes like a diff tool.
It renders standard Markdown plus KaTeX math, Shiki code highlighting and Mermaid diagrams, with a two-pane table of contents that highlights as you scroll, image lightbox zooming, GitHub-style alert blocks, and links to other .md files that open in a new tab automatically.
Its watch mode monitors the open file for external changes, computing and color-coding line-level diffs with added lines in green and removed lines struck through in red, with a floating toolbar to step through each change and a running summary of lines added and removed.
It supports multiple tabs, full-text search, a quick edit mode, PDF, HTML and Markdown export, light and dark themes with custom CSS themes, and a distraction-free zen mode; it is built with Tauri v2 in Rust and React, and installs as a Windows installer or a macOS disk image.