Rule Definition
These exploit IE parsing quirks to target specific versions.

Remediation
Use feature queries, responsive design, or progressive enhancement instead.

Violation Code Sample

* html .box {
  width: 300px; /* IE6 */
}

*+html .box {
  width: 320px; /* IE7 */
}

Fixed Code Sample

.box {
  width: 320px;
}

/* If you really need conditional styles, use classes or data attributes set server-side */
.legacy .box {
  width: 300px;
}

http://interactivevolcano.com/ie-specific-css-styles https://dev.to/koolkamalkishor/css-techniques-for-cross-browser-compatibility-and-styling-2cp4 MDN – Browser compatibility & feature detection: https://developer.mozilla.org/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/Feature_detection W3C – CSS Conformance (standards-compliant parsing): https://www.w3.org/TR/CSS21/conform.html