Expandable cards animation not smooth

Im testing the expandable cards on cordova and android device.
the device is Samsung galaxy s10

the open and close animation are sluggish and feel like a low frame rate.
i used the same example on the docs. nothing changed. and the page only have the example code.

all the rest of the app is smooth and nice

This is because Android browser is extremly slow when it is about rendering blur effects. You can simplify card backdrop blur by adding these CSS rules to your styles:

.card-backdrop {
  animation: none !important;
  transition: 400ms;
.card-backdrop-in {
  background-color: rgba(0,0,0,0.2);