diff --git a/.storybook/mocks/README.md b/.storybook/mocks/README.md
index cc4396933..e9f4defd9 100644
--- a/.storybook/mocks/README.md
+++ b/.storybook/mocks/README.md
@@ -3,7 +3,6 @@
 The following files:
 
 - mediawiki.mixins
-- mediawiki.mixins.animation
 - mediawiki.mixins.less
 
 are LESS files containing one-line imports that correspond to files in
diff --git a/.storybook/mocks/custom.less b/.storybook/mocks/custom.less
index cfe706f56..261909ddc 100644
--- a/.storybook/mocks/custom.less
+++ b/.storybook/mocks/custom.less
@@ -26,12 +26,10 @@ body {
  * NOTE: To test the animation, remove these rules.
  */
 .mwe-popups-fade-in-up {
-	-webkit-animation: none;
 	animation: none;
 }
 
 .mwe-popups-fade-in-down {
-	-webkit-animation: none;
 	animation: none;
 }
 
diff --git a/.storybook/storybook-resources.sh b/.storybook/storybook-resources.sh
index 0b5826ade..0e00cbed0 100755
--- a/.storybook/storybook-resources.sh
+++ b/.storybook/storybook-resources.sh
@@ -7,7 +7,6 @@ curl -sSL "https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/skins/Vector
 
 # MediaWiki LESS mixins
 curl https://raw.githubusercontent.com/wikimedia/mediawiki/master/resources/src/mediawiki.less/mediawiki.mixins.less -o .storybook/mocks/mediawiki.mixins.less
-curl https://raw.githubusercontent.com/wikimedia/mediawiki/master/resources/src/mediawiki.less/mediawiki.mixins.animation.less -o .storybook/mocks/mediawiki.mixins.animation.less
 
 # mediawiki.ui variables
 curl https://raw.githubusercontent.com/wikimedia/mediawiki/master/resources/src/mediawiki.less/mediawiki.ui/variables.less -o .storybook/mocks/mediawiki.ui/variables.less
diff --git a/src/ui/mixins.less b/src/ui/mixins.less
index 12beaa561..012ef34bf 100644
--- a/src/ui/mixins.less
+++ b/src/ui/mixins.less
@@ -1,4 +1,3 @@
-@import 'mediawiki.mixins.animation.less';
 @import 'mediawiki.mixins.less';
 
 /*
@@ -35,42 +34,20 @@
 	left: @left;
 }
 
-.mwe-popups-translate( @x, @y ) {
-	-webkit-transform: translate( @x, @y );
-	-ms-transform: translate( @x, @y );
-	transform: translate( @x, @y );
-}
-
 /* FIXME: Use Phuedx's approach to make this cleaner
    https://gist.github.com/phuedx/0639a279b6efb1a71474 */
-@-webkit-keyframes mwe-popups-fade-in-up {
-	.mwe-popups-fade-in-up-frames;
-}
-
 @keyframes mwe-popups-fade-in-up {
 	.mwe-popups-fade-in-up-frames;
 }
 
-@-webkit-keyframes mwe-popups-fade-in-down {
-	.mwe-popups-fade-in-down-frames;
-}
-
 @keyframes mwe-popups-fade-in-down {
 	.mwe-popups-fade-in-down-frames;
 }
 
-@-webkit-keyframes mwe-popups-fade-out-down {
-	.mwe-popups-fade-out-down-frames;
-}
-
 @keyframes mwe-popups-fade-out-down {
 	.mwe-popups-fade-out-down-frames;
 }
 
-@-webkit-keyframes mwe-popups-fade-out-up {
-	.mwe-popups-fade-out-up-frames;
-}
-
 @keyframes mwe-popups-fade-out-up {
 	.mwe-popups-fade-out-up-frames;
 }
@@ -78,63 +55,63 @@
 .mwe-popups-fade-in-up-frames() {
 	0% {
 		opacity: 0;
-		.mwe-popups-translate( 0, 20px );
+		transform: translate( 0, 20px );
 	}
 
 	100% {
 		opacity: 1;
-		.mwe-popups-translate( 0, 0 );
+		transform: translate( 0, 0 );
 	}
 }
 
 .mwe-popups-fade-in-down-frames() {
 	0% {
 		opacity: 0;
-		.mwe-popups-translate( 0, -20px );
+		transform: translate( 0, -20px );
 	}
 
 	100% {
 		opacity: 1;
-		.mwe-popups-translate( 0, 0 );
+		transform: translate( 0, 0 );
 	}
 }
 
 .mwe-popups-fade-out-down-frames() {
 	0% {
 		opacity: 1;
-		.mwe-popups-translate( 0, 0 );
+		transform: translate( 0, 0 );
 	}
 
 	100% {
 		opacity: 0;
-		.mwe-popups-translate( 0, 20px );
+		transform: translate( 0, 20px );
 	}
 }
 
 .mwe-popups-fade-out-up-frames() {
 	0% {
 		opacity: 1;
-		.mwe-popups-translate( 0, 0 );
+		transform: translate( 0, 0 );
 	}
 
 	100% {
 		opacity: 0;
-		.mwe-popups-translate( 0, -20px );
+		transform: translate( 0, -20px );
 	}
 }
 
 .mwe-popups-fade-in-up {
-	.animation( mwe-popups-fade-in-up, 0.2s, ease, forwards );
+	animation: mwe-popups-fade-in-up 0.2s ease forwards;
 }
 
 .mwe-popups-fade-in-down {
-	.animation( mwe-popups-fade-in-down, 0.2s, ease, forwards );
+	animation: mwe-popups-fade-in-down 0.2s ease forwards;
 }
 
 .mwe-popups-fade-out-down {
-	.animation( mwe-popups-fade-out-down, 0.2s, ease, forwards );
+	animation: mwe-popups-fade-out-down 0.2s ease forwards;
 }
 
 .mwe-popups-fade-out-up {
-	.animation( mwe-popups-fade-out-up, 0.2s, ease, forwards );
+	animation: mwe-popups-fade-out-up 0.2s ease forwards;
 }
diff --git a/src/ui/templates/popup/popup.less b/src/ui/templates/popup/popup.less
index 3de59f041..aaf92bfd5 100644
--- a/src/ui/templates/popup/popup.less
+++ b/src/ui/templates/popup/popup.less
@@ -109,8 +109,6 @@
 			/* @noflip */
 			right: 0;
 			/* @noflip */
-			background-image: -webkit-linear-gradient( to right, rgba( 255, 255, 255, 0 ), rgba( 255, 255, 255, 1 ) 50% );
-			/* @noflip */
 			background-image: linear-gradient( to right, rgba( 255, 255, 255, 0 ), rgba( 255, 255, 255, 1 ) 50% );
 		}
 
@@ -118,8 +116,6 @@
 			/* @noflip */
 			left: 0;
 			/* @noflip */
-			background-image: -webkit-linear-gradient( to left, rgba( 255, 255, 255, 0 ), rgba( 255, 255, 255, 1 ) 50% );
-			/* @noflip */
 			background-image: linear-gradient( to left, rgba( 255, 255, 255, 0 ), rgba( 255, 255, 255, 1 ) 50% );
 		}
 
@@ -129,8 +125,6 @@
 			/* @noflip */
 			bottom: 0;
 			/* @noflip */
-			background-image: -webkit-linear-gradient( to bottom, rgba( 255, 255, 255, 0 ), rgba( 255, 255, 255, 1 ) 75% );
-			/* @noflip */
 			background-image: linear-gradient( to bottom, rgba( 255, 255, 255, 0 ), rgba( 255, 255, 255, 1 ) 75% );
 		}
 		/* stylelint-enable function-linear-gradient-no-nonstandard-direction */
@@ -364,36 +358,36 @@
 // Position the SVG border
 .mwe-popups-is-tall {
 	polyline {
-		.mwe-popups-translate( 0, 0 );
+		transform: translate( 0, 0 );
 	}
 
 	&.flipped-x-y {
 		polyline {
-			.mwe-popups-translate( 0, -8px );
+			transform: translate( 0, -8px );
 		}
 	}
 
 	&.flipped-x {
 		polyline {
-			.mwe-popups-translate( 0, 8px );
+			transform: translate( 0, 8px );
 		}
 	}
 }
 
 .rtl .mwe-popups-is-tall {
 	polyline {
-		.mwe-popups-translate( -100%, 0 );
+		transform: translate( -100%, 0 );
 	}
 
 	&.flipped-x-y {
 		polyline {
-			.mwe-popups-translate( -100%, -8px );
+			transform: translate( -100%, -8px );
 		}
 	}
 
 	&.flipped-x {
 		polyline {
-			.mwe-popups-translate( -100%, 8px );
+			transform: translate( -100%, 8px );
 		}
 	}
 }
diff --git a/src/ui/templates/referencePreview/referencePreview.less b/src/ui/templates/referencePreview/referencePreview.less
index ea5e4c0b6..ce05cbb68 100644
--- a/src/ui/templates/referencePreview/referencePreview.less
+++ b/src/ui/templates/referencePreview/referencePreview.less
@@ -51,7 +51,6 @@
 			width: 100%;
 			height: @lineHeight;
 			background-color: transparent;
-			background-image: -webkit-linear-gradient( top, rgba( 255, 255, 255, 0 ), rgba( 255, 255, 255, 1 ) );
 			background-image: linear-gradient( rgba( 255, 255, 255, 0 ), rgba( 255, 255, 255, 1 ) );
 			opacity: 0;
 			pointer-events: none; // Allows clicking "through" the element