Mixins may not be defined within control directives or other mixins

ERROR in ./node_modules/css-loader?{"sourceMap":false,"importLoaders":1}!./node_modules/postcss-loader?{"ident":"postcss"}!./node_modules/sass-loader/lib/loader.js?{"sourceMap":false,"precision":8,"includePaths":[]}!./src/app/@theme/styles/styles.scss
Module build failed:
undefined
^
Mixins may not be defined within control directives or other mixins.
in C:\Users\AJ\Desktop\temptadmin-master\node_modules\@nebular\theme\components\checkbox\_checkbox.component.theme.scss (line 8, column 10)
Error:
undefined
^
Mixins may not be defined within control directives or other mixins.
in C:\Users\AJ\Desktop\temptadmin-master\node_modules\@nebular\theme\components\checkbox\_checkbox.component.theme.scss (line 8, column 10)
at options.error (C:\Users\AJ\Desktop\temptadmin-master\node_modules\node-sass\lib\index.js:291:26)
@ ./src/app/@theme/styles/styles.scss 4:14-214
@ multi ./node_modules/bootstrap/dist/css/bootstrap.css ./node_modules/typeface-exo/index.css ./node_modules/roboto-fontface/css/roboto/roboto-fontface.css ./node_modules/ionicons/scss/ionicons.scss ./node_modules/font-awesome/scss/font-awesome.scss ./node_modules/nebular-icons/scss/nebular-icons.scss ./node_modules/socicon/css/socicon.css ./node_modules/pace-js/templates/pace-theme-flash.tmpl.css ./src/app/@theme/styles/styles.scss

webpack: Failed to compile.
may not be defined within control directives or other mixins