Yes, you must add all your css files, referring to the vendorNpmFiles file in the angular-cli-build.js First go to the project directory and enter
npm install --save @ng-bootstrap/ng-bootstrap
then open angular-cli-build.js and add this line
vendorNpmFiles: [ 'systemjs/dist/system-polyfills.js', 'systemjs/dist/system.src.js', 'zone.js/dist/**/*.+(js|js.map)', 'es6-shim/es6-shim.js', 'reflect-metadata/**/*.+(ts|js|js.map)', 'rxjs/**/*.+(js|js.map)', '@angular/**/*.+(js|js.map)', 'angularfire2/**/*.js', 'firebase/*.js', '@ng-bootstrap/ng-bootstrap/**/*.+(js|js.map)' ]
now open src / system-config.ts, write
const map: any = { '@ng-bootstrap/ng-bootstrap': 'vendor/@ng-bootstrap/ng-bootstrap' };
and
const packages: any = { '@ng-bootstrap/ng-bootstrap': { defaultExtension: 'js', main: 'index.js' }, '@ng-bootstrap/ng-bootstrap/accordion': { defaultExtension: 'js', main: 'index.js' }, '@ng-bootstrap/ng-bootstrap/alert': { defaultExtension: 'js', main: 'index.js' }, '@ng-bootstrap/ng-bootstrap/buttons': { defaultExtension: 'js', main: 'index.js' }, '@ng-bootstrap/ng-bootstrap/carousel': { defaultExtension: 'js', main: 'index.js' }, '@ng-bootstrap/ng-bootstrap/collapse': { defaultExtension: 'js', main: 'index.js' }, '@ng-bootstrap/ng-bootstrap/dropdown': { defaultExtension: 'js', main: 'index.js' }, '@ng-bootstrap/ng-bootstrap/pagination': { defaultExtension: 'js', main: 'index.js' }, '@ng-bootstrap/ng-bootstrap/popover': { defaultExtension: 'js', main: 'index.js' }, '@ng-bootstrap/ng-bootstrap/progressbar': { defaultExtension: 'js', main: 'index.js' }, '@ng-bootstrap/ng-bootstrap/rating': { defaultExtension: 'js', main: 'index.js' }, '@ng-bootstrap/ng-bootstrap/tabset': { defaultExtension: 'js', main: 'index.js' }, '@ng-bootstrap/ng-bootstrap/timepicker': { defaultExtension: 'js', main: 'index.js' }, '@ng-bootstrap/ng-bootstrap/tooltip': { defaultExtension: 'js', main: 'index.js' }, '@ng-bootstrap/ng-bootstrap/typeahead': { defaultExtension: 'js', main: 'index.js' } };