--- a/browser/themes/shared/identity-block/identity-block.inc.css
+++ b/browser/themes/shared/identity-block/identity-block.inc.css
@@ -1,14 +1,22 @@
 %if 0
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 %endif
 
+:root {
+  --identity-block-extra-spacing: 8px;
+}
+
+:root[uidensity=compact] {
+  --identity-block-extra-spacing: 4px;
+}
+
 #identity-box {
   padding-inline-start: 8px;
   padding-inline-end: 4px;
   margin-inline-end: 4px;
   /* Set default fill for icons in the identity block.
      Individual icons can override this. */
   fill: currentColor;
   fill-opacity: .6;
@@ -50,26 +58,26 @@
 #urlbar[pageproxystate=valid] > #identity-box.verifiedIdentity {
   --urlbar-separator-color: rgba(18, 188, 0, .5);
 }
 
 #urlbar[pageproxystate=valid] > #identity-box.verifiedIdentity,
 #urlbar[pageproxystate=valid] > #identity-box.chromeUI,
 #urlbar[pageproxystate=valid] > #identity-box.extensionPage,
 #urlbar-display-box {
-  margin-inline-end: 8px;
+  margin-inline-end: var(--identity-block-extra-spacing);
   border-inline-end: 1px solid var(--urlbar-separator-color);
   border-image: linear-gradient(transparent 15%, var(--urlbar-separator-color) 15%, var(--urlbar-separator-color) 85%, transparent 85%);
   border-image-slice: 1;
 }
 
 #urlbar[pageproxystate=valid] > #identity-box.verifiedIdentity,
 #urlbar[pageproxystate=valid] > #identity-box.chromeUI,
 #urlbar[pageproxystate=valid] > #identity-box.extensionPage {
-  padding-inline-end: 8px;
+  padding-inline-end: var(--identity-block-extra-spacing);
 }
 
 #urlbar-display-box {
   padding-inline-start: 4px;
   border-inline-start: 1px solid var(--urlbar-separator-color);
   border-image: linear-gradient(transparent 15%, var(--urlbar-separator-color) 15%, var(--urlbar-separator-color) 85%, transparent 85%);
   border-image-slice: 1;
 }