diff --git a/stacks/homepage/conf/custom.css b/stacks/homepage/conf/custom.css
index 5422f8c..7606e02 100644
--- a/stacks/homepage/conf/custom.css
+++ b/stacks/homepage/conf/custom.css
@@ -130,11 +130,22 @@
 html,
 body,
 #page_wrapper,
+#background,
 body > div {
   background-color: var(--bg-0) !important;
   background-image: none !important;
 }
 
+/* `#background` above is load-bearing, not defensive tidiness. Homepage
+   server-renders the wallpaper as an INLINE style on `<div id="background">`,
+   and Next.js caches that rendered page — so removing the `background:` block
+   from settings.yaml is not enough on its own. A restart does not clear it;
+   only a full recreate does, and recreating this container has its own cost
+   (the tab bar and i18n go missing for up to an hour and then heal on their
+   own). Enforcing it in the stylesheet is deterministic, immediate, and also
+   means the canvas stays correct if the setting is ever re-added by accident.
+   The deliberate absence of the config block is documented in settings.yaml. */
+
 body {
   font-family: var(--font-sans) !important;
   color: var(--fg-1);
diff --git a/stacks/homepage/theme/australis.css.in b/stacks/homepage/theme/australis.css.in
index 795224d..13b3a99 100644
--- a/stacks/homepage/theme/australis.css.in
+++ b/stacks/homepage/theme/australis.css.in
@@ -110,11 +110,22 @@
 html,
 body,
 #page_wrapper,
+#background,
 body > div {
   background-color: var(--bg-0) !important;
   background-image: none !important;
 }
 
+/* `#background` above is load-bearing, not defensive tidiness. Homepage
+   server-renders the wallpaper as an INLINE style on `<div id="background">`,
+   and Next.js caches that rendered page — so removing the `background:` block
+   from settings.yaml is not enough on its own. A restart does not clear it;
+   only a full recreate does, and recreating this container has its own cost
+   (the tab bar and i18n go missing for up to an hour and then heal on their
+   own). Enforcing it in the stylesheet is deterministic, immediate, and also
+   means the canvas stays correct if the setting is ever re-added by accident.
+   The deliberate absence of the config block is documented in settings.yaml. */
+
 body {
   font-family: var(--font-sans) !important;
   color: var(--fg-1);