appear.css

.list-transition-enter, .list-transition-appear {
/*We give the list the initial dimension of the list button*/
top: 0;
width: 120px;
max-height: 40px;
color: transparent;
background-color: #5a564c;
}
/* This is where we can add the transition*/
.list-transition-enter-active, .list-transition-appear-active {
top: 45px;
width: 200px;
max-height: 200px;
background-color: #9e8949;
transition: all 400ms;
}