PliegoCSS

Compile confidence into CSS.

Standards-first CSS analysis, typed Rust authoring, deterministic artifacts, and controlled migration without a styling runtime.

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Important

0.1.0-rc.2 is public-preview software distributed from the public canonical repository. The nineteen PliegoCSS crates form one exact-version compatibility unit and are published on crates.io and replayed from the registry with Rust 1.85 after the complete hosted CI and CodeQL matrices passed. 0.1.0 remains blocked by the machine readiness record. Core formats and selected APIs are frozen candidates; beta and experimental capabilities may still change.

Why PliegoCSS?

CSS tooling often asks teams to choose between ordinary CSS, typed authoring, static analysis, and reproducible build evidence. PliegoCSS puts those workflows behind one Rust implementation while keeping the browser contract simple: the output is static standards-compliant CSS with no styling runtime or WebAssembly requirement.

PliegoCSS is designed around four principles:

• Standards first — normal CSS remains a first-class input and output.
• Fail closed — unsupported or ambiguous analysis is reported instead of guessed.
• Deterministic artifacts — CSS, manifests, findings, source maps, token graphs, and receipts are hash-bound and reproducible.
• Incremental adoption — audit an existing project first; typed Rust styles and reversible migration tools are optional layers.

What PliegoCSS does

Area	Current capability
Standard CSS	Audit, compatibility findings, budgets, accessibility guards, transform/minify
Typed Rust	Compile-time checked pc! and pcx! literals with stable style identities
Tokens and themes	TOML themes, DTCG 2025.10 resolver inputs, aliases, provenance, token graphs
Build evidence	Canonical manifests, findings, Source Map v3, control receipts, read-only drift checks
Adoption	Sass/Tailwind/CSS Modules inventory and bounded reversible Tailwind projections
Usage	Generated StyleId analysis and conservative generic-CSS declaration observations
Tooling	CLI, stdio LSP, VS Code client candidate, Neovim client candidate
Automation	Bounded repair plans, exact edits, authorization, rollback, verification receipts

The exact maturity and claim boundaries are maintained in the product maturity map. Competitive coverage is tracked honestly in the Tailwind CSS v4.3.2 matrix.

Quick start

Requirements

• Rust 1.85 or newer
• Git
• Node.js and pnpm are required only for repository development and full verification

Install the public-preview CLI from crates.io:

cargo install pliego-cssc --version '=0.1.0-rc.2' --locked

Or clone the repository and build locally:

git clone https://github.com/celiumsai/pliegocss
cd pliegocss
cargo build --locked -p pliego-cssc

1. Audit ordinary CSS

pliego-cssc audit \
  --input app.css \
  --targets baseline-widely \
  --format human

Machine-readable output is available as canonical JSON or SARIF:

pliego-cssc audit --input app.css --targets baseline-widely --format json
pliego-cssc audit --input app.css --targets baseline-widely --format sarif

2. Transform CSS without changing the authored source

pliego-cssc transform-css \
  --input app.css \
  --output dist/app.css \
  --targets modern \
  --format minified

Add --check in CI to detect output drift without writing files.

3. Compile typed Rust styles

use pliego_css::{pc, Style};

fn button() -> Style {
    pc!(
        "inline-flex items-center gap-2 rounded-lg bg-accent px-4 py-2 \
         text-sm font-semibold text-white hover:bg-accent-strong \
         focus-visible:ring-2 disabled:opacity-50"
    )
}

Compile visible literals from a Rust source tree:

pliego-cssc compile \
  --source src \
  --seed \
  --theme \
  --output dist/app.css \
  --manifest dist/app.manifest.json

Unknown utilities, invalid domains, conflicting declarations, and contradictory variants fail during compilation rather than becoming silent runtime behavior.

CLI workflows

Controlled artifact publication

A controlled compile publishes CSS and its evidence as one rollback-capable group:

mkdir -p dist/control
pliego-cssc compile \
  --source src \
  --seed \
  --theme \
  --output dist/control/app.css \
  --manifest dist/control/app.manifest.json \
  --control-dir dist/control

The group can include:

• generated CSS;
• Source Map v3;
• specialized manifest;
• canonical token graph;
• findings document;
• control manifest;
• build receipt.

Repeat the command with --check for read-only verification.

DTCG resolver input

pliego-cssc compile \
  --style "flex bg-brand" \
  --tokens examples/product.resolver.json \
  --token-input appearance=dark \
  --theme \
  --output dist/app.css

Resolver paths and selections are explicit. JSON token files are never silently discovered.

Bundle plans

pliego-cssc bundle \
  --plan pliego.bundles.toml \
  --output-dir dist/bundles \
  --control

Bundle plans provide explicit source ownership, route/island partitions, optional reachability pruning, Asset Plans, and Project Index output.

Conservative migration inventory

pliego-cssc migration-project-inventory ./existing-project
pliego-cssc migration-project-plan migration-project.json

Migration proposals remain automatic: false. Apply operations require exact before-bytes and hashes, and rollback refuses to overwrite drifted files. See the reversible migration contract.

Generic CSS usage evidence

pliego-cssc generic-css-usage \
  --findings pliego.css.findings.json \
  --observed observed-identities.json \
  --scope browser-session-1 \
  --output pliego.css.generic-usage.json

Only positive evidence becomes observed; missing evidence remains unknown and is never relabeled as dead CSS.

Architecture

ordinary CSS ───────────────┐
Rust pc!/pcx! literals ─────┼─> parser / source inventory
TOML or DTCG tokens ────────┘            │
                                          v
                                semantic IR + policy
                                          │
                    ┌─────────────────────┼─────────────────────┐
                    v                     v                     v
               static CSS          findings/SARIF      manifests/receipts

The workspace is split into small crates with explicit boundaries:

• pliego-css — application-facing typed API and macros;
• pliego-cssc — command-line interface;
• pliego-css-build — compilation, CSS audit, findings, and artifacts;
• pliego-css-config / pliego-css-theme — themes, DTCG, policy, and token graphs;
• pliego-css-control — canonical control manifests and receipts;
• pliego-css-source — source and migration inventory;
• pliego-css-io / pliego-css-publication — bounded I/O and grouped publication;
• pliego-css-lsp — bounded LSP 3.18 server;
• pliego-css-agent — repair and verification boundary.

All nineteen publishable crates share one exact version and are packaged in dependency order.

Evidence and compatibility

The release candidate is exercised by hosted CI on:

• Ubuntu with Rust 1.85 and 1.96;
• Windows with Rust 1.85 and 1.96;
• macOS with Rust 1.85 and 1.96;
• bounded fuzz, package extraction/replay, WASM checks, rustdoc, Clippy, and deterministic artifacts.

Local Chrome and Edge computed-style gates cover selected standard-CSS and migration projections. Firefox and Safari/WebKit behavior is not claimed where no corresponding browser replay exists. Likewise, the accessibility analyzer provides bounded static evidence and does not claim WCAG certification.

Documentation

Topic	Link
Documentation index	docs/index.md
First compile	docs/getting-started/first-compile.md
CLI reference	docs/reference/cli.md
Public API candidate	docs/reference/public-api.md
Compatibility policy	docs/reference/compatibility.md
Themes and tokens	docs/learn/themes-and-tokens.md
Maturity map	docs/product/maturity-map.md
Release readiness	docs/product/release-readiness-0.1.0.md
Release process	docs/contributing/release-process.md
Changelog	CHANGELOG.md

Development

cargo test --workspace --all-targets --locked
cargo clippy --workspace --all-targets --locked -- -D warnings
cargo fmt --all -- --check
node scripts/check-release.mjs fast

The full hosted matrix and release profile add package replay, deterministic concurrency, fuzzing, portability vectors, editor integrations, and optional external corpora.

Project boundaries

PliegoCSS does not:

• replace browser cascade, layout, or paint engines;
• ship a styling runtime or require WASM in the browser;
• infer application ownership from filenames;
• execute Tailwind plugins, Sass importers, or project JavaScript during migration inventory;
• treat missing runtime observations as proof that CSS is dead;
• claim complete Tailwind catalog parity, complete browser support, or WCAG certification.

License

Licensed under the Apache License 2.0.

Copyright © Celiums Solutions LLC.