index.html

<!doctype html>
<html lang="zh-Hans">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<style>
    *{margin:0;padding: 0;box-sizing: border-box}
    :root{
        --button-height:32px;
        --font-size:14px;
        --font-size: white;
        --border-radius:4px;
        --button-active-bg:#eee;
        --color:#333;
        --border-color:#999;
        --border-color-hover:#666;
        --button-bg:white;
    }
    #app{
        margin: 2px;
    }
    body{
        font-size:var(--font-size)
    }
</style>
<style>

</style>
<body>
<div id="app">
   <g-button class="g-button"></g-button>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<script src="./src/app.js"></script>
<script>
new Vue({
    el:'#app',
    data:{
        message:'hi'
    }
})
</script>
</body>
</html>

button.vue

<template>
  <button class="g-button">按钮</button>
</template>
<script>
export  default {


}
</script>
<style lang="scss">
.g-button{
  font-size:var(--font-size);
  height:var(--button-height);
  padding: 0 1em;
  border-radius: var(--border-radius);
  border: 1px solid var(--border-color);
  background: var(--button-bg);

}
&:hover{
  border-color:var(--border-color-hover);
}
&:active{
  background-color:var(--button-active-bg);
}
</style>

app.js

import  Vue from 'vue'
import Button from "./button";
Vue.component('g-button',Button)
new Vue({
    el:'#app'
})