diff --git a/styles.css b/styles.css
index b9bf47e..467332c 100644
--- a/styles.css
+++ b/styles.css
@@ -1239,6 +1239,26 @@ textarea:focus {
 }
 
 @media (max-width: 640px) {
+  body[data-page="cube"] .phase-header {
+    grid-template-columns: minmax(0, 1fr) auto;
+    gap: 0.65rem;
+    padding: 0.8rem 0.9rem;
+  }
+
+  body[data-page="cube"] .phase-title,
+  body[data-page="cube"] .phase-spine .spine-card,
+  body[data-page="cube"] .zone-foot {
+    display: none;
+  }
+
+  body[data-page="cube"] .phase-spine {
+    gap: 0;
+  }
+
+  body[data-page="cube"] .zone-inner {
+    grid-template-rows: auto minmax(0, 1fr);
+  }
+
   .hero-setup h1 {
     font-size: 2.1rem;
   }