<script> 
export default { 
  data() { 
    return {

      className: 'red-color',

    }; 
  }, 
} 
</script> 
<template>

  <h1 v-bind:class="className">Hello, Vue JS</h1>

</template> 
<style>

.red-color {
  color: red;
}

</style>