Vue.js 在鼠标悬停时动态添加和删除类

我可以用Vue在鼠标上成功添加一个类.但我想在鼠标离开元素时删除该类.Vue中处理这个问题的惯用方法是什么？

<template>
  <div id="navigation">
    <div class="nav-container">
      <nav>
        <router-link to="/" class="home">Ping Party</router-link>
        <div class="navigation-actions">
          <router-link to="/sign_in" v-if="!isLoggedIn" class="sign_in">Sign In</router-link>
          <router-link to="/sign_up" v-if="!isLoggedIn" @mouseover.native="mouseOver" class="sign_up" ref="sign_up">Sign Up</router-link>
          <router-link to="/users" v-if="isLoggedIn" class="users">Users</router-link>
          <v-btn :click.prevent="signOut()" v-if="isLoggedIn">Sign Out</v-btn>
        </div>
      </nav>
    </div>
  </div>
</template>

<script>
  import SignUp from "../forms/SignUp";
  import SignIn from "../forms/SignIn";

  export default {
    components: {
      SignUp,
      SignIn
    },
    computed: {
      isLoggedIn () {
        return this.$store.getters.isLoggedIn
      }
    },
    methods: {
      signOut: function() {
        this.$store.commit("LOGOUT")
        this.$store.commit("FLASH_MESSAGE", {
          message: "Signed Out Successfully",
          show: true,
          styleClass: "error",
          timeOut: 4000
        })
        this.$router.push('/')
      },
      mouseOver: function() {
        this.$refs.sign_up.$vnode.elm.classList.add("hovered")
      }
    }
  }
</script>

正如您在mouseover上看到的，我调用了mouseover函数，这成功地将类添加到元素中.但现在，当用户离开元素时，类仍然存在.当用户离开元素时，如何让类移除？谢谢你的帮助.