diff --git a/_quarto.yml b/_quarto.yml
index 50b9f95..fc5d9b8 100644
--- a/_quarto.yml
+++ b/_quarto.yml
@@ -14,7 +14,9 @@ website:
         href: https://twitter.com/NSIDC
 format:
   html:
-    theme: cosmo
+    theme: 
+      light: ["flatly", default]
+      dark: ["darkly", default]
     css: styles.css