diff --git a/src/index.css b/src/index.css
index 4ef7b1e..901c750 100755
--- a/src/index.css
+++ b/src/index.css
@@ -145,12 +145,21 @@
 @layer base {
   :root {
     color-scheme: light;
+    /* The parts the browser draws for itself. `accent-color` is what tints a
+       native radio or checkbox — left unset it is the platform blue, which is
+       the one colour on screen belonging to no theme here. */
+    accent-color: var(--budget-accent);
   }
 
   .dark {
     color-scheme: dark;
   }
 
+  ::selection {
+    background: var(--budget-accent);
+    color: var(--budget-accent-ink);
+  }
+
   body {
     /* Was `grid place-items-center`, which centred short pages VERTICALLY —
        the month view floated in the middle of the viewport on an empty month.