Typo.css is a mature, single-file CSS library that provides a comprehensive reset and typography system optimized for Chinese (CJK) web content. It normalizes browser defaults and exposes a `.typo` class container that applies advanced typographic features: CJK-optimized font stacks (sans, serif, mono, kai, fangsong) via CSS custom properties, proper line-height, line-break strictness, Han-Western spacing via `text-autospace`, punctuation trimming via `text-spacing-trim`, hanging punctuation, native emphasis marks with fallback, ruby annotation support, vertical writing mode helper, and readable line-length constraints. The library is dependency-free, uses progressive enhancement (e.g., `@supports` for native emphasis and script-specific generics), and includes a suite of modifier classes for common typographic needs. A comprehensive test suite (Node.js assertion-based) verifies the CSS contract, and detailed documentation explains the design rationale based on W3C CLReq and other standards. The demo page demonstrates real-world usage with SEO metadata. This is a production-ready library for any project requiring high-quality Chinese text rendering, and it is actively maintained with modern CSS best practices.