Merge pull request #5836 from matrix-org/gsouquet-readreceipts-animation

res/css/_common.scss

@@ -28,6 +28,16 @@ $MessageTimestamp_width_hover: calc($MessageTimestamp_width - 2 * $EventTile_e2e
 
 :root {
     font-size: 10px;
+
+    --transition-short: .1s;
+    --transition-standard: .3s;
+}
+
+@media (prefers-reduced-motion) {
+    :root {
+        --transition-short: 0;
+        --transition-standard: 0;
+    }
 }
 
 html {

res/css/views/rooms/_EventTile.scss

@@ -283,6 +283,10 @@ $left-gutter: 64px;
     display: inline-block;
     height: $font-14px;
     width: $font-14px;
+
+    transition:
+        left var(--transition-short) ease-out,
+        top var(--transition-standard) ease-out;
 }
 
 .mx_EventTile_readAvatarRemainder {