CKEDITOR.stylesSet.add( 'my_styles', [
    // Block-level styles.
    { name: 'Blue Title', element: 'h2', styles: { color: 'Blue' } },
    { name: 'Red Title',  element: 'h3', styles: { color: 'Red' } },

    // Inline styles.
    { name: 'CSS Style', element: 'span', attributes: { 'class': 'my_style' } },
    { name: 'Marker: Yellow', element: 'span', styles: { 'background-color': 'Yellow' } }
]);