Index: src/wp-content/themes/twentytwentyone/assets/css/style-dark-mode-rtl.css
===================================================================
--- src/wp-content/themes/twentytwentyone/assets/css/style-dark-mode-rtl.css	(revision 52597)
+++ src/wp-content/themes/twentytwentyone/assets/css/style-dark-mode-rtl.css	(working copy)
@@ -21,6 +21,10 @@
 		filter: brightness(0.85) contrast(1.1);
 	}
 
+	.is-dark-theme .wp-block-cover.is-light .has-background-dim {
+		opacity: 0.2;
+	}
+
 	.respect-color-scheme-preference.is-dark-theme body {
 		background-color: var(--global--color-background);
 	}
Index: src/wp-content/themes/twentytwentyone/assets/css/style-dark-mode.css
===================================================================
--- src/wp-content/themes/twentytwentyone/assets/css/style-dark-mode.css	(revision 52597)
+++ src/wp-content/themes/twentytwentyone/assets/css/style-dark-mode.css	(working copy)
@@ -21,6 +21,10 @@
 		filter: brightness(0.85) contrast(1.1);
 	}
 
+	.is-dark-theme .wp-block-cover.is-light .has-background-dim {
+		opacity: 0.2;
+	}
+
 	.respect-color-scheme-preference.is-dark-theme body {
 		background-color: var(--global--color-background);
 	}
Index: src/wp-content/themes/twentytwentyone/assets/sass/style-dark-mode.scss
===================================================================
--- src/wp-content/themes/twentytwentyone/assets/sass/style-dark-mode.scss	(revision 52597)
+++ src/wp-content/themes/twentytwentyone/assets/sass/style-dark-mode.scss	(working copy)
@@ -21,6 +21,10 @@
 		filter: brightness(.85) contrast(1.1);
 	}
 
+	.is-dark-theme .wp-block-cover.is-light .has-background-dim {
+		opacity: 0.2;
+	}
+
 	.respect-color-scheme-preference.is-dark-theme body {
 		background-color: var(--global--color-background);
 	}