App.vue
main.js
 
<template>
  <h1>Basic CSS Transition</h1>
  <button @click="this.doesRotate = true">Rotate</button>
  <div :class="{ rotate: doesRotate }"></div>
</template>

<script>
export default {
  data() {
    return {
      doesRotate: false
    }
  }
}
</script>

<style scoped>
  .rotate {
    rotate: 160deg;
    transition: rotate 1s;
  }
  div {
    border: solid black 2px;
    background-color: lightcoral;
    width: 60px;
    height: 60px;
  }
  h1, button, div {
    margin: 10px;
  }
</style>                  
import { createApp } from 'vue'

import App from './App.vue'

const app = createApp(App)
app.mount('#app')
                  
http://localhost:5173/