Very good the guide.

I would like to know your opinions about/deep/ selector.

It turns out that the father needs a change in the child only in the visual. I do not know if this violates FIRST.

This feature is implemented in 12.2.0 (vue-loader) May 2017
Issue:vuejs/vue-loader#661

I like this feature because it avoids increasing the code in the child components.
For example, create aprops in the child just to increase the space (margin/padding) instyle inline and then one moreprops to change other styles. It does not sound good to me.

/deep/ selector example:

<template>    <icon name="phone" /></template><style scoped>    .link:hover /deep/ .icon svg {        fill: white;    }</style>