Developer Tools
Extract CSS Supports Rules
Extract CSS @supports feature-query conditions from pasted stylesheets, style blocks, and component CSS without rendering, fetching, or uploading code.
0 / 30,000 characters. No upload, storage, or account required.
CSS supports-rule extraction workflows
Use this extractor when pasted styles need a browser-local inventory of feature-query conditions before compatibility review or documentation.
Audit progressive enhancement
Pair supports rules with Extract CSS Container Queries, Extract CSS Media Queries, and Extract CSS Property Names.
Review modern CSS usage
Use Extract CSS Selectors, Extract CSS Layer Names, and CSS Formatter while documenting source patterns.
Clean copied output
Send extracted rows to Remove Duplicate Lines, Sort Lines, or Normalize Whitespace.
What this tool does
Extract CSS Supports Rules finds @supports conditions in pasted CSS, removes duplicate rows, shows source lines, and runs locally in your browser.
Common use cases
Extract CSS @supports feature-query conditions from pasted stylesheets, component CSS, design-system files, or copied source before compatibility audits, progressive enhancement review, migration, QA, or documentation handoffs.
Use Extract CSS Supports Rules when you are working with copied API payloads, logs, encoded values, config snippets, identifiers, or debugging data and need a quick browser-local check before pasting the result into docs, tickets, tests, or another developer tool.
How to use it
- Paste CSS, style tags, component styles, design-system files, or copied source that contains @supports feature queries.
- Choose whether duplicate rows should be removed and whether output should be normalized for comparison.
- Review extracted supports-rule rows with source lines, then copy the clean list for compatibility audits, progressive enhancement reviews, or migration notes.
Example workflow
Copy a small payload or encoded value from an API response, request URL, log line, or config file. Run the focused check here, confirm the output is readable, then continue with related developer data tools such as validation, formatting, decoding, timestamp conversion, or CSV/JSON conversion.
Privacy note
Extract CSS Supports Rules runs locally in your browser. Your pasted CSS is not uploaded, rendered, fetched, crawled, executed, stored, or logged.
FAQ
Does Extract CSS Supports Rules test browser support?
No. It scans pasted CSS as text and does not run compatibility checks, render pages, fetch assets, upload, store, or log snippets.
Which supports rules are included?
It finds @supports feature-query conditions exactly as written, including property checks, selector checks, not, and, and or expressions.
When is this useful?
Use it while auditing progressive enhancement, documenting modern CSS features, checking migration risks, or preparing compatibility review notes.
Explore more tools
Browse the Developer Tools hub or continue with the Developer Data Toolkit when this task is part of a larger workflow.