diff --git a/src/browser/base/content/zen-styles/zen-tabs/vertical-tabs.css b/src/browser/base/content/zen-styles/zen-tabs/vertical-tabs.css
index 049c88ab7..7ffe0b312 100644
--- a/src/browser/base/content/zen-styles/zen-tabs/vertical-tabs.css
+++ b/src/browser/base/content/zen-styles/zen-tabs/vertical-tabs.css
@@ -267,6 +267,14 @@
       scale: var(--zen-active-tab-scale);
     }
 
+    & .tab-icon-image {
+      &:not([src]),
+      &:-moz-broken {
+        content: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='100' height='100'%3E%3C/svg%3E") !important;
+        background: color-mix(in srgb, var(--zen-primary-color) 70%, transparent 30%);
+      }
+    }
+
     max-width: unset;
     padding: 0 !important;