Error: no mixin named box-shadow

I am having trouble getting the Paper theme to compile properly because there is no mixin named box-shadow, so any inclusion of it fails

.navbar {
  border: none;
  @include box-shadow(0 1px 2px rgba(0,0,0,.3));
...

This is also failing for Error: no mixin named placeholder Any help is appreciated, thanks!

[ChristianClassen]

I just had the same issue when using Bootstrap and Bootswatch, installed via Rails Assets, with Rails 5.0

I did the following to resolve the issue and hope I helps somebody else:

1. Add to Gemfile

source 'https://rails-assets.org' do
  gem 'rails-assets-bootstrap-sass-official', '3.3.7'
end

1. Copy Bootswatch Theme files from Github into vendor/assets folder

• vendor/assets/stylesheets/bootswatch/[theme_name]/_variables.scss
• vendor/assets/stylesheets/bootswatch/[theme_name]/_bootswatch.scss

1. Use @import in Manifest file (application.css.scss)

@import "bootswatch/[theme_name]/variables";
@import "bootstrap-sass-official";
@import "bootswatch/[theme_name]/bootswatch";

[stphane]

I encountered this issue using v3.3.7 SCSS “Lumen” theme, along with a PHP scss parser, neither grunt nor Less. Prompted errors said like there were a bunch of missing mixins.

Undefined mixin box-shadow: line: 35 Undefined mixin transition: line: 310 …

Imports statements seamed to be ordered the right way though

@import "../../web/bootswatch/lumen/_variables.scss";
@import "../../web/bootswatch/lumen/_bootstrap.scss";
@import "../../web/bootswatch/lumen/_bootswatch.scss";

I could stop this issue by replacing “/bootswatch/lumen/_bootstrap.scss” with “bootstrap-sass/assets/stylesheets/_bootstrap.scss”. (Simply run bower install bootstrap-sass-official -S to get bootstrap original scss main file). Error disappeared but still I have to check that the theme is not broken.
It’s like “_bootstrap.scss” and _bootswatch.scss override files belong to differents versions.

Thank you for sharing such nice and neat themes !