diff --git a/frontend/public/global.css b/frontend/public/global.css
index d1663a4..d659a69 100644
--- a/frontend/public/global.css
+++ b/frontend/public/global.css
@@ -66,6 +66,10 @@
 	--radius-lg: calc(2 * var(--radius-unit));
 	--radius-xl: calc(3.25 * var(--radius-unit));
 	--radius-xxl: calc(5.25 * var(--sradius-unit));
+
+	/* initial values. these will be modified by javascript */
+	--viewportWidth: 100vw;
+	--viewportHeight: 100vh;
 }
 
 html, body {