I've added bootstrap to an Angular app created with Angular-CLI (ng new), after adding bootstrap to the project and referencing it from my .angular-cli.json file - ng serve wouldn't run.        
ERROR LOG
ERROR in multi ./src/styles.css C:/server/node_modules/bootstrap/dist/css/bootstrap.css
Module not found: Error: Can't resolve 'C:\server\node_modules\bootstrap\dist\css\bootstrap.css' in 'C:\dev\mean\ems-mean\client\node_mod
ules\@angular\cli\models\webpack-configs'
resolve 'C:\server\node_modules\bootstrap\dist\css\bootstrap.css' in 'C:\dev\mean\ems-mean\client\node_modules\@angular\cli\models\webpac
k-configs'
  using description file: C:\dev\mean\ems-mean\client\node_modules\@angular\cli\package.json (relative path: ./models/webpack-configs)
    Field 'browser' doesn't contain a valid alias configuration
  after using description file: C:\dev\mean\ems-mean\client\node_modules\@angular\cli\package.json (relative path: ./models/webpack-confi
gs)
    No description file found
    no extension`enter code here`
      Field 'browser' doesn't contain a valid alias configuration
      C:\server\node_modules\bootstrap\dist\css\bootstrap.css doesn't exist
    .ts
      Field 'browser' doesn't contain a valid alias configuration
      C:\server\node_modules\bootstrap\dist\css\bootstrap.css.ts doesn't exist
    .js
      Field 'browser' doesn't contain a valid alias configuration
      C:\server\node_modules\bootstrap\dist\css\bootstrap.css.js doesn't exist
    as directory
          C:\server\node_modules\bootstrap\dist\css\bootstrap.css doesn't exist
    [C:\server\node_modules\bootstrap\dist\css\bootstrap.css\package.json]
    [C:\server\node_modules\bootstrap\dist\css\bootstrap.css]
    [C:\server\node_modules\bootstrap\dist\css\bootstrap.css.ts]
    [C:\server\node_modules\bootstrap\dist\css\bootstrap.css.js]
    [C:\server\node_modules\bootstrap\dist\css\bootstrap.css]
     @ multi ./src/styles.css C:/server/node_modules/bootstrap/dist/css/bootstrap.css
