diff --git a/tests/test_homepage.py b/tests/test_homepage.py
index ec60713..d437651 100644
--- a/tests/test_homepage.py
+++ b/tests/test_homepage.py
@@ -7,6 +7,7 @@ fetching climate helpers are not called at all.
 """
 import datetime
 import json
+import pathlib
 import time
 
 import pytest
@@ -134,6 +135,25 @@ def test_hero_locate_has_a_status_slot(client, no_feed):
     assert 'aria-live="polite"' in html
 
 
+def test_homepage_brand_keeps_the_lockup_styling(client, no_feed):
+    """The homepage renders the brand as <p class="site-name"> so the hero owns
+    the page's only h1. The lockup styling is written against `.brand h1`, so
+    the class MUST be matched there too — otherwise the brand silently falls
+    back to block layout, which baseline-aligns the mark instead of centring it
+    and drops the monospace wordmark. Nothing else catches this: the page still
+    renders, and every other test still passes, while the header looks wrong.
+    """
+    html = client.get(f"{B}/").text
+    assert 'class="site-name"' in html
+    assert "<h1 class=\"site-name\"" not in html      # the hero owns the h1
+
+    css = (pathlib.Path(__file__).parents[2] / "frontend" / "style.css").read_text()
+    lockup = css.split(".brand h1", 1)[1].split("}", 1)[0]
+    assert ".brand .site-name" in lockup, (
+        "the .brand h1 lockup rule must also match .brand .site-name"
+    )
+
+
 def test_city_chips_all_resolve(client, no_feed):
     """Every homepage chip must be a real, routable city — a stale slug would
     render an empty chip list and leak a 404 link."""