diff --git a/inst/rmarkdown/templates/posterdown_ids/resources/template.html b/inst/rmarkdown/templates/posterdown_ids/resources/template.html
index f8cab50..f98cb48 100644
--- a/inst/rmarkdown/templates/posterdown_ids/resources/template.html
+++ b/inst/rmarkdown/templates/posterdown_ids/resources/template.html
@@ -456,6 +456,23 @@
 body {
   line-height: 1.2 !important;
 }
+
+/* Firefox column fixes */
+@-moz-document url-prefix() {
+  .poster_body_wrap {
+    height: calc($if(poster_height)$$poster_height$$else$1189mm$endif$ - $if(titlebox_height)$$titlebox_height$$else$17%$endif$ - 40mm) !important;
+    overflow: hidden !important;
+  }
+  .poster_body {
+    column-count: $if(column_numbers)$$column_numbers$$else$2$endif$ !important;
+    column-fill: auto !important;
+    column-gap: 20mm !important;
+    display: block !important;
+    height: 100% !important;
+    max-height: calc($if(poster_height)$$poster_height$$else$1189mm$endif$ - $if(titlebox_height)$$titlebox_height$$else$17%$endif$ - 60mm) !important;
+    overflow: hidden !important;
+  }
+}
 </style>
 $if(custom_css)$
 <link rel="stylesheet" href=$custom_css$>