[11:07:48] Starting 'styles-reload'...
[11:07:48] gulp-inject 2 files into index.scss.
[11:07:48] [Sass] Error in plugin 'gulp-sass'

Message:
    src/app/index.scss
  7:14  Undefined variable: "$gray-lighter".
Details:
    formatted: Error: Undefined variable: "$gray-lighter".
        on line 7 of stdin
>> $text-color: $gray-lighter;
   -------------^

    column: 14
    line: 7
    file: stdin
    status: 1
    messageFormatted: src/app/index.scss
  7:14  Undefined variable: "$gray-lighter".
[11:07:48] Finished 'styles-reload' after 47 ms