diff --git a/src/fontra/client/css/tooltip.css b/src/fontra/client/css/tooltip.css
index ea81f64b1..0255f07b6 100644
--- a/src/fontra/client/css/tooltip.css
+++ b/src/fontra/client/css/tooltip.css
@@ -5,7 +5,7 @@
 
 [data-tooltip]:hover::before {
   content: attr(data-tooltip);
-  font-size: 10px;
+  font-size: 1em;
   text-align: center;
   position: absolute;
   display: block;