vue js override component css

1// in CompA (the parent)
2
3<template>
4  ...
5  <!-- Vue provides built-in class and style props for all comps -->
6  <compb class="compb"></compb>  
7</template>
8
9<script>
10  ...
11</script>
12
13<style lang="scss">
14  #app .compb .compb-header { 
15    color: red; 
16  }
17</style>
18
19<style lang="scss" scoped>
20  ...
21</style>
22