diff --git a/src/apps/gameboard/tests/integrated/test_views.py b/src/apps/gameboard/tests/integrated/test_views.py
index 6c7a476..aa65262 100644
--- a/src/apps/gameboard/tests/integrated/test_views.py
+++ b/src/apps/gameboard/tests/integrated/test_views.py
@@ -640,6 +640,49 @@ class MySeaPickerPhaseTemplateTest(TestCase):
         self.assertNotContains(response, "my-sea-picker")
 
 
+class MySeaPolarityMatchesMySignTest(TestCase):
+    """Bug 2026-05-21 (user-reported): a levity sig chosen on /billboard/
+    my-sign/ rendered as gravity-styled on /gameboard/my-sea/ (priUser bg
+    + secUser text) — and vice versa for gravity sigs (which then collided
+    w. the hardcoded --secUser corner-rank color in `.sea-sig-card`,
+    making the rank + suit-icon invisible against a --secUser bg).
+
+    Root cause was a polarity inversion in `my_sea.html:10` —
+    `{% if significator_reversed %}gravity{% else %}levity{% endif %}` —
+    opposite of `my_sign.html:22` + its JS `_polarity()`. This test pins
+    the two surfaces to agree on the same `User.significator_reversed`
+    → `data-polarity` mapping, so any future drift gets caught."""
+
+    def setUp(self):
+        from apps.epic.models import personal_sig_cards
+        self.user = User.objects.create(email="polarity@test.io")
+        self.client.force_login(self.user)
+        target = personal_sig_cards(self.user)[0]
+        self.user.significator = target
+        self.user.save(update_fields=["significator"])
+
+    def test_unreversed_sig_renders_gravity_on_both_surfaces(self):
+        """`significator_reversed=False` (the on-creation default) renders
+        data-polarity="gravity" on BOTH my_sign + my_sea — the convention
+        established by my_sign's Sprint 4a picker + its `_polarity()` JS."""
+        self.user.significator_reversed = False
+        self.user.save(update_fields=["significator_reversed"])
+        sea = self.client.get(reverse("my_sea")).content.decode()
+        sign = self.client.get(reverse("billboard:my_sign")).content.decode()
+        self.assertIn('data-polarity="gravity"', sea)
+        self.assertIn('data-polarity="gravity"', sign)
+
+    def test_reversed_sig_renders_levity_on_both_surfaces(self):
+        """`significator_reversed=True` (FLIP-toggled on my_sign) renders
+        data-polarity="levity" on BOTH surfaces."""
+        self.user.significator_reversed = True
+        self.user.save(update_fields=["significator_reversed"])
+        sea = self.client.get(reverse("my_sea")).content.decode()
+        sign = self.client.get(reverse("billboard:my_sign")).content.decode()
+        self.assertIn('data-polarity="levity"', sea)
+        self.assertIn('data-polarity="levity"', sign)
+
+
 class MySeaSpreadFormTemplateTest(TestCase):
     """Sprint 5 iter 3 — form col + SPREAD dropdown structure + default-
     spread context + cross's `data-spread-shape` attribute. Iter 3 spec
diff --git a/src/static_src/scss/_card-deck.scss b/src/static_src/scss/_card-deck.scss
index 4e1d215..1cb0fee 100644
--- a/src/static_src/scss/_card-deck.scss
+++ b/src/static_src/scss/_card-deck.scss
@@ -1364,13 +1364,20 @@ $sea-card-h: 6.5rem;
     position: relative;
     z-index: 2;
 
+    // Corner-rank + suit-icon track `color` so the polarity rules below
+    // (which set `.sig-stage-card { color: ... }` to --priUser for levity)
+    // flip the contrast w. the card's bg. The default (gravity, --priUser
+    // bg) inherits --secUser from the `.sig-stage-card.sea-sig-card` rule
+    // below; the levity polarity rule overrides `.sig-stage-card { color }`
+    // to --priUser, which propagates down through currentColor.
     .fan-corner-rank {
         font-size: 1.2rem;
         font-weight: 700;
         line-height: 1;
-        color: rgba(var(--secUser), 0.85);
+        color: currentColor;
+        opacity: 0.85;
     }
-    i { font-size: 1rem; color: rgba(var(--secUser), 0.75); }
+    i { font-size: 1rem; color: currentColor; opacity: 0.75; }
 }
 
 // .sig-stage-card is normally scoped inside .sig-stage — re-apply the card shell
@@ -1384,6 +1391,7 @@ $sea-card-h: 6.5rem;
     border-radius: 0.5rem;
     background: rgba(var(--priUser), 1);
     border: 0.15rem solid rgba(var(--secUser), 0.6);
+    color: rgba(var(--secUser), 1);  // default (gravity) text color; `[data-polarity="levity"] .sig-stage-card { color: --priUser }` overrides for levity. Corner-rank + suit-icon track currentColor.
     display: flex;
     flex-direction: column;
     position: relative;
diff --git a/src/templates/apps/gameboard/my_sea.html b/src/templates/apps/gameboard/my_sea.html
index 52dfeb6..ff6bda9 100644
--- a/src/templates/apps/gameboard/my_sea.html
+++ b/src/templates/apps/gameboard/my_sea.html
@@ -7,7 +7,7 @@
 {% block content %}
     <div class="my-sea-page"
          data-phase="{% if show_picker %}picker{% else %}landing{% endif %}"
-         data-polarity="{% if significator_reversed %}gravity{% else %}levity{% endif %}">
+         data-polarity="{% if significator_reversed %}levity{% else %}gravity{% endif %}">
         {% if not user_has_sig %}
             {# Sprint 4b sign-gate. The draw UX is gated behind a saved      #}
             {# significator — render a Look!-formatted Brief-style line w.  #}