Adding /deep/ to your selectors

deep.js

/*
This POC sample uses CSS transform which you can install from 
https://www.npmjs.org/package/csstransform

Save this to deep.js and just run via node
*/

var css = __dirname + '/vendor/bootstrap.css';
var target = __dirname + '/dist/bootstrap-deep.css';

var csstransform = require('csstransform');
var csst = csstransform(css);
csst.transformSelectorText({
    prepend: '/deep/',
    // Match all CSS selectors. Use "([^\r\n,{}]+)(,(?=[^}]*{)|\s*{)" or the below.
    match: "/^(-?<=#|\.|\#)(-?[_a-zA-Z]+[_a-zA-Z0-9-]*)(?=[^}]+{)*$/g" 
});
csst.toString(target);