# gss/engine

GSS engine

Repository: https://github.com/gss/engine
Canonical: https://ross.abutalabs.com/products/gss-engine
Homepage: http://gss.github.io
Language: CoffeeScript
License: MIT
License Family: permissive
Last push: 2019-12-17T00:22:16+00:00

## Health v2 (maintenance only)
Score: 23/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 4841, "days_push": 2452, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2853, forks 100 (observed 2026-08-28T04:07:25.747950+00:00)

## What it is
GSS (Grid Style Sheets) is a JavaScript engine that compiles and runs constraint-based layout rules for the DOM, implementing Constraint Cascading Style Sheets via the Cassowary constraint solver. It supports CCSS constraints and Apple's Visual Format Language to express relational positioning and sizing between elements.

## Use cases
- center an element within another with a one-liner
- define relational layout rules between DOM elements
- replace CSS layout with constraint-based positioning
- use Apple's Visual Format Language for web layout
- solve cyclic layout dependencies between elements
- build responsive layouts from size and position constraints

## When to choose
- you need declarative relational constraints between elements rather than parent-relative CSS positioning
- you want Cassowary-style constraint solving like Apple's Auto Layout in the browser
- you're maintaining an existing GSS codebase

## When to avoid
- starting a new project — modern CSS Flexbox and Grid cover most needs and GSS is no longer actively developed
- you need guaranteed long-term support or recent browser feature integration
- performance-critical pages where a JS layout solver runtime would add overhead

## Facets
- artifact type: library
- maturity: maintenance
- function: ui-components, css-framework, compiler
- domain: web-development, frontend, web-design
- platform: browser
- tags: constraint-solver, layout-engine, cassowary, visual-format-language, ccss, css-polyfill, coffeescript, nodejs, javascript

## Member repositories
- gss/engine (main) score 23

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:25.747950+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T07:36:46.931483+00:00, confidence not recorded.
  - readme: https://github.com/gss/engine (fetched 2026-08-28T04:07:25.747950+00:00, sha e842604d5827)
  - homepage: http://gss.github.io (fetched 2026-08-29T09:52:40.372471+00:00, sha cabed230dba4)
- Data as of 2026-08-30T08:39:29.467469+00:00.