half-screen-dialog.wxss

.weui-demo-dialog{
  visibility:hidden;
  opacity:0;
  transition:all .3s;
}
.weui-half-screen-dialog{
  transition:all .3s;
  transform:translateY(100%);
}
.weui-demo-dialog_show{
  visibility:visible;
  opacity:1;
}
.weui-demo-dialog_show .weui-half-screen-dialog{
    transform:translateY(0);
}