Gruntfile.js

'use strict';

module.exports = function(grunt) {

  // Project configuration.
  grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'),
    notify: {
      watch: {
        options: {
          title: 'Done Grunting!',
          message: 'SASS complete.'
        }
      }
    },
    dirs: {
      dirs: {
        dest: 'lib/',
        scss: 'scss/',
        js: 'js/'
      },
    },
    bower: {
      dev: {
        dest: '<% dirs.dest %>',
        options: {
          stripJsAffix: false
        }
      }
    },
    bowerInstall: {
      install: {
        options: {
          verbose: true,
          layout: 'byType',
          cleanTargetDir: true
        }
      }
    },
    rename: {
      scss: {
        src: 'lib/scss/flexslider/flexslider.css',
        dest: 'scss/flexslider.scss'
      }
    },
    concat: {
      libs: {
        files: {
          'js/head.lib.js' : [ 'lib/js/modernizr/modernizr.js' ],
          'js/script.lib.js' : [ 'lib/js/jquery/jquery.js','lib/js/flexslider/jquery.flexslider.js','lib/js/isotope/jquery.isotope.js' ]
        }
      },
      script: {
        files: {
          'js/script.dev.js' : [ 'js/script.lib.js','js/script.js' ]
        }
      },
      head: {
        files: {
          'js/head.dev.js' : [ 'js/head.lib.js','js/head.js' ]
        }
      }
    },
    uglify: {
      head: {
        files: {
          'js/head.min.js' : [ 'js/head.dev.js' ]
        }
      },
      script: {
        files: {
          'js/script.min.js' : [ 'js/script.dev.js' ]
        }
      }
    },
    sass: {
      options: {
        trace: true,
        compass: false,
        loadPath: [
          'lib/matter/'
        ]
      },
      dist: {
        options: {
          style: 'compressed'
        },
        files: {
          'style.css' : 'scss/style.scss',
          'style-admin.css' : 'scss/admin.scss'
        }
      },
      dev: {
        options: {
          style: 'expanded'
        },
        files: {
          'style.css' : 'scss/style.scss',
          'style-admin.css' : 'scss/admin.scss'
        }
      }
    },
    watch: {
      options: {
        livereload: true
      },
      scss: {
        files: 'scss/*',
        tasks: [ 'sass:dev' ]
      },
      head: {
        files: [ 'js/head.js' ],
        tasks: [ 'concat:head' ]
      },
      script: {
        files: [ 'js/script.js' ],
        tasks: [ 'concat:script' ]
      },
      libs: {
        files: [ 'js/*.lib.js' ],
        tasks: [ 'concat:libs' ]
      },
      uglify: {
        files: 'js/*.dev.js',
        tasks: [ 'uglify' ]
      }
    }
  });

  grunt.loadNpmTasks( 'grunt-bower-task' );

  grunt.renameTask( 'bower', 'bowerInstall' );
  
  grunt.loadNpmTasks( 'grunt-bower' );
  grunt.loadNpmTasks( 'grunt-rename' );
  grunt.loadNpmTasks( 'grunt-contrib-sass' );
  grunt.loadNpmTasks( 'grunt-contrib-watch' );
  grunt.loadNpmTasks( 'grunt-contrib-concat' );
  grunt.loadNpmTasks( 'grunt-contrib-uglify' );
  grunt.loadNpmTasks( 'grunt-notify' );
  
  grunt.registerTask( 'default', [ 'build', 'watch' ] );
  
  grunt.registerTask( 'build', [ 'bowerInstall', 'bower', 'rename', 'concat', 'sass', 'uglify' ] );
  
  grunt.registerTask( 'prod', [ 'sass:dist', 'uglify' ] );
};

eh um, it's Sass not SASS ;)