/*
Error: Undefined mixin 'box-sizing'.
        on line 17 of /Users/dmitrychuba/Sites/Adam/gregorypeck.com/wp-content/themes/gregorypeck/prepros/scss/popup.scss, in `box-sizing'
        from line 17 of /Users/dmitrychuba/Sites/Adam/gregorypeck.com/wp-content/themes/gregorypeck/prepros/scss/popup.scss

12: //    height : 100%;
13: //}
14: 
15: #tribute-popup {
16:     * {
17:         @include box-sizing(border-box);
18:     }
19: 
20:     .page-title {
21:         // top : 0;
22:         // left : 0;

Backtrace:
/Users/dmitrychuba/Sites/Adam/gregorypeck.com/wp-content/themes/gregorypeck/prepros/scss/popup.scss:17:in `box-sizing'
/Users/dmitrychuba/Sites/Adam/gregorypeck.com/wp-content/themes/gregorypeck/prepros/scss/popup.scss:17
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:349:in `block in visit_mixin'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/stack.rb:98:in `block in with_mixin'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/stack.rb:115:in `with_frame'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/stack.rb:98:in `with_mixin'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:347:in `visit_mixin'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/base.rb:36:in `visit'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:158:in `block in visit'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/stack.rb:79:in `block in with_base'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/stack.rb:115:in `with_frame'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/stack.rb:79:in `with_base'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:158:in `visit'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:431:in `block (2 levels) in visit_rule'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:431:in `map'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:431:in `block in visit_rule'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:179:in `with_environment'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:429:in `visit_rule'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/base.rb:36:in `visit'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:158:in `block in visit'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/stack.rb:79:in `block in with_base'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/stack.rb:115:in `with_frame'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/stack.rb:79:in `with_base'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:158:in `visit'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:431:in `block (2 levels) in visit_rule'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:431:in `map'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:431:in `block in visit_rule'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:179:in `with_environment'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:429:in `visit_rule'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/base.rb:36:in `visit'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:158:in `block in visit'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/stack.rb:79:in `block in with_base'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/stack.rb:115:in `with_frame'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/stack.rb:79:in `with_base'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:158:in `visit'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/base.rb:52:in `block in visit_children'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/base.rb:52:in `map'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/base.rb:52:in `visit_children'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:167:in `block in visit_children'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:179:in `with_environment'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:166:in `visit_children'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/base.rb:36:in `block in visit'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:186:in `visit_root'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/base.rb:36:in `visit'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:157:in `visit'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/visitors/perform.rb:8:in `visit'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/root_node.rb:36:in `css_tree'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/tree/root_node.rb:29:in `render_with_sourcemap'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/engine.rb:378:in `_render_with_sourcemap'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/engine.rb:295:in `render_with_sourcemap'
/Applications/CodeKit.app/Contents/Resources/engines/compass/compass-import-once/lib/compass/import-once/engine.rb:23:in `block in render_with_sourcemap'
/Applications/CodeKit.app/Contents/Resources/engines/compass/compass-import-once/lib/compass/import-once/engine.rb:29:in `with_import_scope'
/Applications/CodeKit.app/Contents/Resources/engines/compass/compass-import-once/lib/compass/import-once/engine.rb:22:in `render_with_sourcemap'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/plugin/compiler.rb:490:in `update_stylesheet'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/plugin/compiler.rb:215:in `block in update_stylesheets'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/plugin/compiler.rb:209:in `each'
/Applications/CodeKit.app/Contents/Resources/engines/scss/lib/sass/plugin/compiler.rb:209:in `update_stylesheets'
/Applications/CodeKit.app/Contents/Resources/engines/compass/compass/lib/compass/sass_compiler.rb:40:in `compile!'
/Applications/CodeKit.app/Contents/Resources/engines/compass/compass/lib/compass/commands/update_project.rb:49:in `perform'
/Applications/CodeKit.app/Contents/Resources/engines/compass/compass/lib/compass/commands/base.rb:18:in `execute'
/Applications/CodeKit.app/Contents/Resources/engines/compass/compass/lib/compass/commands/project_base.rb:19:in `execute'
/Applications/CodeKit.app/Contents/Resources/engines/compass/compass/lib/compass/exec/sub_command_ui.rb:43:in `perform!'
/Applications/CodeKit.app/Contents/Resources/engines/compass/compass/lib/compass/exec/sub_command_ui.rb:15:in `run!'
/Applications/CodeKit.app/Contents/Resources/engines/compass/compass/bin/compass:52:in `block in <main>'
/Applications/CodeKit.app/Contents/Resources/engines/compass/compass/bin/compass:66:in `call'
/Applications/CodeKit.app/Contents/Resources/engines/compass/compass/bin/compass:66:in `<main>'
*/
body:before {
  white-space: pre;
  font-family: monospace;
  content: "Error: Undefined mixin 'box-sizing'.\A         on line 17 of /Users/dmitrychuba/Sites/Adam/gregorypeck.com/wp-content/themes/gregorypeck/prepros/scss/popup.scss, in `box-sizing'\A         from line 17 of /Users/dmitrychuba/Sites/Adam/gregorypeck.com/wp-content/themes/gregorypeck/prepros/scss/popup.scss\A \A 12: //    height : 100%;\A 13: //}\A 14: \A 15: #tribute-popup {\A 16:     * {\A 17:         @include box-sizing(border-box);\A 18:     }\A 19: \A 20:     .page-title {\A 21:         // top : 0;\A 22:         // left : 0;"; }