diff --git a/.changeset/popular-hounds-sin.md b/.changeset/popular-hounds-sin.md
new file mode 100644
index 0000000000..56e3614d67
--- /dev/null
+++ b/.changeset/popular-hounds-sin.md
@@ -0,0 +1,5 @@
+---
+'@primer/css': patch
+---
+
+Fix styles for ::backdrop
diff --git a/src/support/mixins/color-modes.scss b/src/support/mixins/color-modes.scss
index 0ca2b89a31..ea1bf4e451 100644
--- a/src/support/mixins/color-modes.scss
+++ b/src/support/mixins/color-modes.scss
@@ -31,7 +31,7 @@
     }
 
     ::backdrop,
-    [data-color-mode="light"][data-light-theme="#{$theme-name}"],
+    [data-color-mode="light"][data-light-theme="#{$theme-name}"]::backdrop,
     [data-color-mode="dark"][data-dark-theme="#{$theme-name}"]::backdrop {
       @content;
 
@@ -47,6 +47,14 @@
         @content;
       }
     }
+    
+    ::backdrop,
+    [data-color-mode="light"][data-light-theme="#{$theme-name}"]::backdrop,
+    [data-color-mode="dark"][data-dark-theme="#{$theme-name}"]::backdrop {
+      @content;
+
+      /*! */ // Must remain separate from the above selector to not break browsers which don't support ::backdrop, e.g. Safari 14.
+    }
   }
 
   @media (prefers-color-scheme: light) {
@@ -56,6 +64,12 @@
         @content;
       }
     }
+    
+    [data-color-mode="auto"][data-light-theme="#{$theme-name}"]::backdrop {
+      @content;
+
+      /*! */ // Must remain separate from the above selector to not break browsers which don't support ::backdrop, e.g. Safari 14.
+    }
   }
 
   @media (prefers-color-scheme: dark) {
@@ -65,6 +79,12 @@
         @content;
       }
     }
+    
+    [data-color-mode="auto"][data-light-theme="#{$theme-name}"]::backdrop {
+      @content;
+
+      /*! */ // Must remain separate from the above selector to not break browsers which don't support ::backdrop, e.g. Safari 14.
+    }
   }
 }