Kilotest: Diagnoses of invalid at-rule
violation by HTML element 0 on Next Generation Playground page
Basics
About the Next Generation Playground page
- URL: https://www.playnextgeneration.com/
- Tested 14 days ago by job
cg9on 2026-05-18 at 15:01
About HTML element 0
- Tag name:
HTML - Text: [not applicable]
- Start tag:
<html lang="en" style="scroll-padding-top: 151px;"> - XPath:
/html - Bounding box: x = 0, y = 0, width = 1920, height = 1080
About the invalid at-rule
issue
- Why it matters: Document cannot be properly displayed in particular contexts
- Priority: high
- Related WCAG standard: 4.1
Diagnoses
Here is how tools diagnose the invalid at-rule
issue for HTML element 0 of the Next Generation Playground page.
- CSS: Unrecognized at-rule @container
Tool: Html Checker API (World Wide Web Consortium)
- CSS: Unrecognized at-rule @container
Tool: Html Checker API (World Wide Web Consortium)
- CSS: Unrecognized at-rule @container
Tool: Html Checker API (World Wide Web Consortium)
- CSS: Unrecognized at-rule @container
Tool: Html Checker API (World Wide Web Consortium)