code: function _process( content ) {
      var reg = /((?:\/\/.*?\n)|(?:\/\*[\s\S]*?\*\/))|(?:@import\s([\s\S]*?)(?:\n|$)(?!\s+[^{@]*\n))/ig;
      // var reg = /@import[\s\S]*?;/ig;
      var rUrl = /^url/i;
      var rEnd = /;$/;
  
      content = fixLineBreak( content );
  
      return content.replace( reg, function( all, comments, value ) {
          var files;
  
          value = value ? value.trim().replace( rEnd, '' ) : '';
  
          // If it's comments or If the @import has any media queries.
          if ( comments || /('|").*?\1\s+[^'"]+$/.exec(value) ) {
              return all;
          }
  
          files = value.split(/\s*,?\s+/m).map(function( value ) {
              var quote = '',
                  match;
  
              value = value.trim();
              match = /^('|")(.*)\1$/.exec( value );
  
              if ( match ) {
                  value = match[ 2 ];
                  quote = match[ 1 ];
              }
  
              // If the file’s extension is .css.
              if ( /\.css$/i.exec( value ) ||
  
                  // If the filename begins with http://.
                  /^http/i.exec( value ) ||
  
                  // If the filename is a url().
                  /^url/i.exec( value ) ) {
                  return '@import ' + quote + value + quote + ';';
              }
  
              return map.wrap( value );
          });
  
          return files.join('\n');
      });
  }
docs: 匹配scss内嵌代码：@import 'xxx'; @import 'xxx', 'xxx';