diff --git a/src/themes/applied.css b/src/themes/applied.css
index 70fe9ad82..886c6f3d4 100644
--- a/src/themes/applied.css
+++ b/src/themes/applied.css
@@ -7,6 +7,7 @@ html {
   background-color: var(--wa-color-surface-default);
   padding: 0;
   margin: 0;
+  tab-size: 4;
 }
 
 :is(html, body):has(wa-page) {