when you want to set your styles in just exact component use scoped in style tag
<style scoped></style>
it will fix it and set the styles just on than component
and if you want to add your style in children component just add deep fix set on children component
<style scoped>
.a :deep(.b) {
/* ... */
}
</style>
useage and detail :
<style>
/* global styles */
</style>
<style scoped>
/* local styles */
</style>