diff --git a/core/.stylelintrc.json b/core/.stylelintrc.json
index 5d7632a5037..ec7fc86e13a 100644
--- a/core/.stylelintrc.json
+++ b/core/.stylelintrc.json
@@ -5,7 +5,6 @@
   ],
   "rules": {
     "alpha-value-notation": "number",
-    "at-rule-no-vendor-prefix": null,
     "color-function-notation": "legacy",
     "comment-empty-line-before": null,
     "custom-property-pattern": "^[a-z][-_a-z0-9IE]*$",
diff --git a/core/profiles/demo_umami/themes/umami/css/classy/components/progress.css b/core/profiles/demo_umami/themes/umami/css/classy/components/progress.css
index 47da8893500..c969473f305 100644
--- a/core/profiles/demo_umami/themes/umami/css/classy/components/progress.css
+++ b/core/profiles/demo_umami/themes/umami/css/classy/components/progress.css
@@ -53,16 +53,6 @@
 /**
  * Progress bar animations.
  */
-@-webkit-keyframes animate-stripes {
-  0% { background-position: 0 0, 0 0; }
-  100% { background-position: 0 0, -80px 0; }
-}
-
-@-ms-keyframes animate-stripes {
-  0% { background-position: 0 0, 0 0; }
-  100% { background-position: 0 0, -80px 0; }
-}
-
 @keyframes animate-stripes {
   0% { background-position: 0 0, 0 0; }
   100% { background-position: 0 0, -80px 0; }
diff --git a/core/themes/starterkit_theme/css/components/progress.css b/core/themes/starterkit_theme/css/components/progress.css
index 47da8893500..c969473f305 100644
--- a/core/themes/starterkit_theme/css/components/progress.css
+++ b/core/themes/starterkit_theme/css/components/progress.css
@@ -53,16 +53,6 @@
 /**
  * Progress bar animations.
  */
-@-webkit-keyframes animate-stripes {
-  0% { background-position: 0 0, 0 0; }
-  100% { background-position: 0 0, -80px 0; }
-}
-
-@-ms-keyframes animate-stripes {
-  0% { background-position: 0 0, 0 0; }
-  100% { background-position: 0 0, -80px 0; }
-}
-
 @keyframes animate-stripes {
   0% { background-position: 0 0, 0 0; }
   100% { background-position: 0 0, -80px 0; }