Minification failed. Returning unminified contents.

How to resolve this error ?

/* Minification failed. Returning unminified contents.
(4105,1): run-time error CSS1019: Unexpected token, found '@import'
(4105,9): run-time error CSS1019: Unexpected token, found 'url(/Themes/NopShop/Content/css/http:/fonts.googleapis.com/css?family=Roboto:400,300,400italic,500,700,100)'
(4106,1): run-time error CSS1019: Unexpected token, found '@import'
(4106,9): run-time error CSS1019: Unexpected token, found 'url(/Themes/NopShop/Content/css/http:/fonts.googleapis.com/css?family=Open+Sans:400,800,300,600,700)'
(4107,1): run-time error CSS1019: Unexpected token, found '@import'
(4107,9): run-time error CSS1019: Unexpected token, found 'url(/Themes/NopShop/Content/css/http:/fonts.googleapis.com/css?family=Abel)'
(4262,1): run-time error CSS1019: Unexpected token, found '@-webkit-keyframes'
(4263,5): run-time error CSS1062: Expected semicolon or closing curly-brace, found '0%'
(4454,145): run-time error CSS1036: Expected expression, found ';'
(5376,1): run-time error CSS1019: Unexpected token, found '@-webkit-keyframes'
(5377,5): run-time error CSS1062: Expected semicolon or closing curly-brace, found '0%'
 */

Hi there,
Can you tell me where you have received this error (which online 'minifier' or program you have used)? Do you know that in the 'Admin/General and miscellaneous settings/SEO settings' you can find settings for 'JavaScript bundling and minification' and also 'CSS bundling and minification'. You can use this integrated features from Nop administration directly.