Bug Report: Missing var() in dynamic CSS for search field

I found a minor CSS generation error in the Astra_Dynamic_CSS class. The custom property is missing the var() function, which results in invalid CSS output in the browser for the search field background color.

File: inc/class-astra-dynamic-css.php
Current output: background-color: (--ast-global-dark-bg-style);
Expected output: background-color: var(--ast-global-dark-bg-style);

Here is the exact diff for the fix:

diff --git a/wp-content/themes/astra/inc/class-astra-dynamic-css.php b/wp-content/themes/astra/inc/class-astra-dynamic-css.php
index d0a3ba0..4171482 100644
--- a/wp-content/themes/astra/inc/class-astra-dynamic-css.php
+++ b/wp-content/themes/astra/inc/class-astra-dynamic-css.php
@@ -1036,7 +1036,7 @@ if ( ! class_exists( 'Astra_Dynamic_CSS' ) ) {
 
 				// Reduced specificity so that it does not override customizer background color option.
 				$css_output['.ast-header-search .slide-search .search-field'] = array(
-					'background-color' => '(--ast-global-dark-bg-style)', // Referred by main.css.
+					'background-color' => 'var(--ast-global-dark-bg-style)', // Referred by main.css.
 				);
 			}