function twentyfourteen_custom_header_setup() {
  add_theme_support(
    'custom-header',
    
/**
 * Filters Twenty Fourteen custom-header support arguments.
 *
 * @since Twenty Fourteen 1.0
 *
 * @param array $args {
 *     An array of custom-header support arguments.
 *
 *     @type bool   $header_text            Whether to display custom header text. Default false.
 *     @type int    $width                  Width in pixels of the custom header image. Default 1260.
 *     @type int    $height                 Height in pixels of the custom header image. Default 240.
 *     @type bool   $flex_height            Whether to allow flexible-height header images. Default true.
 *     @type string $admin_head_callback    Callback function used to style the image displayed in
 *                                          the Appearance > Header screen.
 *     @type string $admin_preview_callback Callback function used to create the custom header markup in
 *                                          the Appearance > Header screen.
 * }
 */
    apply_filters(
      'twentyfourteen_custom_header_args',
      array(
        'default-text-color'     => 'fff',
        'width'                  => 1260,
        'height'                 => 240,
        'flex-height'            => true,
        'wp-head-callback'       => 'twentyfourteen_header_style',
        'admin-head-callback'    => 'twentyfourteen_admin_header_style',
        'admin-preview-callback' => 'twentyfourteen_admin_header_image',
      )
    )
  );
}