ant-design/style/core/motion.less

.motion-common() {
  animation-duration: .2s;
  animation-fill-mode: both;
}

.motion-common-leave() {
  animation-duration: .2s;
  animation-fill-mode: both;
}

.make-motion(@className, @keyframeName) {
  .@{className}-enter,
  .@{className}-appear {
    .motion-common();
    animation-play-state: paused;
  }
  .@{className}-leave {
    .motion-common-leave();
    animation-play-state: paused;
  }
  .@{className}-enter.@{className}-enter-active,
  .@{className}-appear.@{className}-appear-active {
    animation-name: ~"@{keyframeName}In";
    animation-play-state: running;
  }
  .@{className}-leave.@{className}-leave-active {
    animation-name: ~"@{keyframeName}Out";
    animation-play-state: running;
  }
}

.ant-motion-collapse {
  overflow: hidden;
  &-active {
    transition: height .2s ease-out;
  }
}

@import "motion/fade";
@import "motion/move";
@import "motion/other";
@import "motion/slide";
@import "motion/swing";
@import "motion/zoom";