diff --git a/ext/css/structured-content.css b/ext/css/structured-content.css
index a79d9ddc4..bebc9e550 100644
--- a/ext/css/structured-content.css
+++ b/ext/css/structured-content.css
@@ -19,6 +19,7 @@
 /* Glossary images */
 .gloss-image-container {
     display: inline-block;
+    font-size: calc(1em / var(--font-size-no-units));
 }
 .gloss-image-link[data-background=true]>.gloss-image-container {
     background-color: var(--gloss-image-background-color);