Astra_Custom_Nav_Walker::start_lvl( string $output, int $depth, array $args = array() )

		public function start_lvl( &$output, $depth = 0, $args = array() ) {

			$indent = str_repeat( "\t", $depth );

			$style = '';

			if ( 0 === $depth && '' != $this->megamenu && 'ast-hf-mobile-menu' !== $args->menu_id ) {

				$style = array(
					'.ast-desktop .menu-item-' . $this->menu_megamenu_item_id . ' .menu-item > .menu-link, .menu-item-' . $this->menu_megamenu_item_id . ' .menu-item .sub-menu > .menu-link, .ast-desktop .ast-container .menu-item-' . $this->menu_megamenu_item_id . ' .menu-item:hover' => array(
						'color' => $this->megamenu_text_color,
					),
					'.ast-container .menu-item-' . $this->menu_megamenu_item_id . ' .menu-item .sub-menu .menu-item:hover, .ast-desktop .ast-container .menu-item-' . $this->menu_megamenu_item_id . ' .menu-item .menu-link:hover, .ast-container .menu-item-' . $this->menu_megamenu_item_id . ' .menu-item .sub-menu .menu-link:hover' => array(
						'color' => $this->megamenu_text_h_color,
					),
				);

				$megamenu_divider_class = '';

				if ( isset( $this->megamenu_divider_color ) && '' != $this->megamenu_divider_color ) {
					$megamenu_divider_class = ' astra-megamenu-has-divider';
					$style[ '.ast-desktop .astra-megamenu-li.menu-item-' . $this->menu_megamenu_item_id . ':hover .astra-megamenu > .menu-item' ] = array(
						'border-right' => '1px solid ' . $this->megamenu_divider_color,
					);
				}

				if ( isset( $this->megamenu_separator_color ) && '' != $this->megamenu_separator_color ) {
					$style['.ast-desktop .astra-megamenu-li .sub-menu .menu-item-heading > .menu-link'] = array(
						'border-bottom' => '1px solid ' . $this->megamenu_separator_color,
					);
				}

				if ( isset( $this->megamenu_bg_image ) ) {

					$bg_object = array(
						'background-color'    => $this->megamenu_bg_color,
						'background-image'    => $this->megamenu_bg_image,
						'background-repeat'   => $this->megamenu_bg_repeat,
						'background-size'     => $this->megamenu_bg_size,
						'background-position' => $this->megamenu_bg_position,
					);

					$style[ '.ast-desktop .astra-megamenu-li.menu-item-' . $this->menu_megamenu_item_id . ' .astra-full-megamenu-wrapper, .ast-desktop .astra-megamenu-li.menu-item-' . $this->menu_megamenu_item_id . ' .astra-mega-menu-width-menu-container, .ast-desktop .astra-megamenu-li.menu-item-' . $this->menu_megamenu_item_id . ' .astra-mega-menu-width-content, .ast-desktop .astra-megamenu-li.menu-item-' . $this->menu_megamenu_item_id . ' .astra-mega-menu-width-custom' ] = astra_get_megamenu_background_obj( $bg_object );
				}

				if ( 'custom' === $this->megamenu_width ) {

					$megamenu_custom_width = $this->megamenu_custom_width;

					$megamenu_custom_width = ( isset( $megamenu_custom_width ) && ! empty( $megamenu_custom_width ) ) ? $megamenu_custom_width : 1200;

					$style[ '.ast-desktop .astra-megamenu-li.menu-item-' . $this->menu_megamenu_item_id . ' .astra-mega-menu-width-custom:before' ] = array(
						'content' => '"' . $megamenu_custom_width . '"',
						'opacity' => 0,
					);
				}

				// Advanced spacing options.
				$margin_object = array(
					'margin-top'    => $this->megamenu_margin_top,
					'margin-right'  => $this->megamenu_margin_right,
					'margin-bottom' => $this->megamenu_margin_bottom,
					'margin-left'   => $this->megamenu_margin_left,
				);

				$style[ '.ast-desktop .astra-megamenu-li.menu-item-' . $this->menu_megamenu_item_id . ' div.astra-full-megamenu-wrapper, .ast-desktop .astra-megamenu-li.menu-item-' . $this->menu_megamenu_item_id . ' ul.astra-mega-menu-width-menu-container, .ast-desktop .astra-megamenu-li.menu-item-' . $this->menu_megamenu_item_id . ' ul.astra-mega-menu-width-content, .ast-desktop .astra-megamenu-li.menu-item-' . $this->menu_megamenu_item_id . ' ul.astra-mega-menu-width-custom' ] = astra_get_megamenu_spacing_css( $margin_object );

				$padding_object = array(
					'padding-top'    => $this->megamenu_padding_top,
					'padding-right'  => $this->megamenu_padding_right,
					'padding-bottom' => $this->megamenu_padding_bottom,
					'padding-left'   => $this->megamenu_padding_left,
				);

				$style[ '.ast-desktop .ast-mega-menu-enabled .astra-megamenu-li.menu-item-' . $this->menu_megamenu_item_id . ' .astra-full-megamenu-wrapper, .ast-desktop .ast-mega-menu-enabled .astra-megamenu-li.menu-item-' . $this->menu_megamenu_item_id . ' .astra-mega-menu-width-menu-container, .ast-desktop .ast-mega-menu-enabled .astra-megamenu-li.menu-item-' . $this->menu_megamenu_item_id . ' .astra-mega-menu-width-content, .ast-desktop .ast-mega-menu-enabled .astra-megamenu-li.menu-item-' . $this->menu_megamenu_item_id . ' .astra-mega-menu-width-custom' ] = astra_get_megamenu_spacing_css( $padding_object );

				Astra_Ext_Nav_Menu_Loader::add_css( astra_parse_css( $style ) );

				if ( 'full' === $this->megamenu_width || 'full-stretched' === $this->megamenu_width ) {
					// Adding "hidden" class to fix the visibility issue during page load.
					$output .= "\n$indent<div " . astra_attr(
						'ast-megamenu-full-attr',
						array(
							'class' => 'astra-full-megamenu-wrapper ast-hidden' . esc_attr( $megamenu_divider_class ),
						)
					) . ">\n";
				}
				// Adding "hidden" class to fix the visibility issue during page load.
				$output .= "\n$indent<ul " . astra_attr(
					'ast-megamenu-attr',
					array(
						'class' => "astra-megamenu sub-menu astra-mega-menu-width-{$this->megamenu_width}" . esc_attr( $megamenu_divider_class ) . ' ast-hidden',
					)
				) . ">\n";

			} elseif ( 2 <= $depth && '' != $this->megamenu ) {
				$output .= "\n$indent<ul class='astra-nested-sub-menu sub-menu'\">\n";
			} else {
				$output .= "\n$indent<ul class=\"sub-menu\">\n";
			}
		}