Every inline and linked stylesheet is parsed. A parse error means the browser discarded a declaration or a whole rule at load time, so styling that looks correct in the source never applied.
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How this rule is weighted
- Importance
- 7 / 10
- How much this matters relative to other rules.
- Confidence
- SPECIFICATION
- A standard says so: HTML, WCAG, an RFC or Google's own documentation.
- Severity
- error
- How the finding is presented when it fails.
- Scoring
- Counts
- A failure costs points in its category.
Impact is importance multiplied by the confidence tier’s weight — SPECIFICATION 1.0, RESEARCH 0.7, EMERGING 0.3, EXPERIMENTAL 0.1. Two rules backed by the same class of evidence therefore always carry the same weight, which is what makes the score reproducible rather than hand-tuned.
What produces this finding
Built at scan time by stylesheet conformance, not from our static registry. That engine evaluates its whole rule set in one pass, so this check cannot be run on its own — it runs as part of a scan.
Questions about this rule
- Does CSS_W3C_PARSE_ERROR affect my score?
- Yes. It is an importance 7 rule at SPECIFICATION confidence, so a failure costs 7 × 1 points of impact in the CSS category before that category is normalised to 100.
- What does SPECIFICATION confidence mean?
- A standard says so: HTML, WCAG, an RFC or Google's own documentation. Confidence is a declared tier rather than a per-rule number, so every rule backed by the same class of evidence carries the same weight - which is what makes the score reproducible instead of hand-tuned.
- How do I check CSS_W3C_PARSE_ERROR on my own site?
- This rule is produced by stylesheet conformance during a scan. stylesheet conformance evaluates its whole rule set in one pass, so this check cannot be run on its own - run the CSS checker and it is included.
Tags
- css
- w3c
- validity
- conformance
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