Compress common CSS property keys

[nmn]

Summary

• add a curated mapping of human-readable 1–3 character shorthands for common CSS properties
• use those shorthands for compressed keys in compiled stylex.create objects
• retain hash-based keys for uncommon properties and conditional declarations
• update compiler, CLI, and Rollup snapshots

This is the first PR in a two-PR stack. Follow-up: #1840.

Test plan

• npm run build
• npm run docs:build
• npm run flow -- --show-all-errors
• npm run typescript
• npm run prettier:report
• npm run lint:report
• npm run test:packages

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1 Skipped Deployment

Project	Deployment	Actions	Updated
stylex	Ignored		Sep 3, 2026 8:26am UTC

[github-actions]

workflow: benchmarks/perf

Comparison of performance test results, measured in operations per second. Larger is better.
yarn workspace v1.22.22
yarn run v1.22.22
$ node ./compare.js /tmp/tmp.TsQjFhrSHO /tmp/tmp.0hZCg2Vl67

Results	Base	Patch	Ratio
babel-plugin: stylex.create
· basic create	746	717	0.96	-
· complex create	97	90	0.93	!!
babel-plugin: stylex.createTheme
· basic themes	600	559	0.93	!!
· complex themes	47	45	0.96	-
Done in 0.06s.
Done in 0.24s.

[github-actions]

workflow: benchmarks/size

Comparison of minified (terser) and compressed (brotli) size results, measured in bytes. Smaller is better.
yarn workspace v1.22.22
yarn run v1.22.22
$ node ./compare.js /tmp/tmp.4y2ortuz1H /tmp/tmp.rOwoWiyQwQ

Results	Base	Patch	Ratio
@stylexjs/stylex/lib/cjs/stylex.js
· compressed	1,535	1,535	1.00
· minified	5,166	5,166	1.00
@stylexjs/stylex/lib/cjs/inject.js
· compressed	1,793	1,793	1.00
· minified	4,915	4,915	1.00
benchmarks/size/.build/bundle.js
· compressed	496,650	486,580	0.98	-
· minified	4,847,840	4,076,568	0.84	!!
benchmarks/size/.build/stylex.css
· compressed	99,757	99,757	1.00
· minified	748,850	748,850	1.00
Done in 0.08s.
Done in 0.32s.