.outer {
  border: 6px solid royalblue;
  width: 300px;
  height: 200px;
  margin: 0 auto;
  overflow-x: hidden;
}

.inner-list {
  display: flex;
  transition: .3s ease-out;
  height: 100%;
}

.inner {
  border: 6px solid olive;
  padding: 0 16px;
}

.button-list {
  text-align: center;
}