diff --git a/static/yaris.css b/static/yaris.css
index 5759562..161573d 100644
--- a/static/yaris.css
+++ b/static/yaris.css
@@ -1,5 +1,12 @@
 /* ── Layout ──────────────────────────────────────────────────────────────── */
 
+/* The UI is designed to look best at ~90% browser zoom, so bake that scale in
+   by shrinking the root font size — every rem-based size (sidebar, typography,
+   spacing) follows. */
+html {
+    font-size: 90%;
+}
+
 :root {
     --sidebar-width: 14rem;
     --sidebar-collapsed-width: 4rem;