public function get_classes( $element = 'overlay' ) {
		$classes = array(
			'overlay'   => array(
				'pum',
				'pum-overlay',
				'pum-theme-' . $this->get_theme_id(),
				'pum-theme-' . $this->get_theme_slug(),
				'popmake-overlay', // Backward Compatibility
			),
			'container' => array(
				'pum-container',
				'popmake', // Backward Compatibility
				'theme-' . $this->get_theme_id(), // Backward Compatibility
			),
			'title'     => array(
				'pum-title',
				'popmake-title', // Backward Compatibility
			),
			'content'   => array(
				'pum-content',
				'popmake-content', // Backward Compatibility
			),
			'close'     => array(
				'pum-close',
				'popmake-close' // Backward Compatibility
			),
		);

		$size = $this->get_setting( 'size', 'medium' );

		if ( in_array( $size, array( 'nano', 'micro', 'tiny', 'small', 'medium', 'normal', 'large', 'xlarge' ) ) ) {
			$classes['container'] = array_merge( $classes['container'], array(
				'pum-responsive',
				'pum-responsive-' . $size,
				'responsive', // Backward Compatibility
				'size-' . $size, // Backward Compatibility
			) );
		} elseif ( $size == 'custom' ) {
			$classes['container'][] = 'size-custom'; // Backward Compatibility
		}

		if ( ! $this->get_setting( 'custom_height_auto' ) && $this->get_setting( 'scrollable_content' ) ) {
			$classes['container'] = array_merge( $classes['container'], array(
				'pum-scrollable',
				'scrollable', // Backward Compatibility
			) );
		}

		if ( $this->get_setting( 'position_fixed' ) ) {
			$classes['container'][] = 'pum-position-fixed';
		}

		if ( $this->get_setting( 'overlay_disabled' ) ) {
			$classes['overlay'][] = 'pum-overlay-disabled';
		}

		if ( $this->get_setting( 'disable_accessibility' ) ) {
			$classes['overlay'][] = 'pum-accessibility-disabled';
		}

		if ( $this->get_setting( 'close_on_overlay_click' ) ) {
			$classes['overlay'][] = 'pum-click-to-close';
		}

		// Add a class for each trigger type.
		foreach ( $this->get_triggers() as $trigger ) {
			if ( ! in_array( $trigger['type'], $classes['overlay'] ) ) {
				$classes['overlay'][] = $trigger['type'];
			}
		}

		if ( is_singular( 'popup' ) ) {
			$classes['overlay'][] = 'pum-preview';
		}


		$classes = apply_filters( 'pum_popup_classes', $classes, $this->ID );

		if ( ! isset( $classes[ $element ] ) ) {
			$classes[ $element ] = array();
		}

		return apply_filters( "pum_popup_{$element}_classes", $classes[ $element ], $this->ID );
	}