[Vue warn]: Property or method "title" is not defined on the instance but referenced during render.为什么提示没有定义呢？求解

<template>  <div>  <p>标题</p>  <input type="text" v-model="title">  <p>内容</p>  <input type="text" v-model="content">  <div>   <button type="button" @click="add()"> 添加</button>  </div>  </div></template><script>import store from '@/store'export default{	name:"Add",	store,	date() {  return{  title:'',  content:'',  }	},	methods:{	add() {        store.commit('addItem',{        title:this.title,        content:this.content        })    }}}</script>