<div id="example-1" class="demo">
  <button @click="show = !show">
    Toggle render
  </button>
  <transition name="slide-fade">
    <p v-if="show">hello</p>
  </transition>
</div>
<script>
new Vue({
  el: '#example-1',
  data: {
    show: true
  }
})
</script>
<style>
.slide-fade-enter-active {
  transition: all .3s ease;
}
.slide-fade-leave-active {
  transition: all .8s cubic-bezier(1.0, 0.5, 0.8, 1.0);
}
.slide-fade-enter, .slide-fade-leave-to {
  transform: translateX(10px);
  opacity: 0;
}
</style>

具体参考文档：
https://cn.vuejs.org/v2/guide/transitions.html#CSS-过渡