demo
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Vue</title>
<script src="https://cdn.bootcss.com/vue/2.2.2/vue.min.js"></script>
</head>
<body>
<div >
<div v-bind:style="{ color: activeColor, fontSize: fontSize + 'px' }">努力向上</div>
</div>
<script>
new Vue({
el: '#six',
data: {
activeColor: 'blue',
fontSize: 20
}
})
</script>
</body>
</html>
效果：