diff --git a/app/item/models.py b/app/item/models.py
index dbd6fe3..708adf9 100644
--- a/app/item/models.py
+++ b/app/item/models.py
@@ -327,5 +327,7 @@ class Week(models.Model):
                         colors.append(f'hsl({color}, 80%, 15%, 0.8)')
                     else:
                         colors.append(f'hsl({color}, 50%, 15%, 0.8)')
+            if len(colors) == 1:
+                colors.append(colors[0].replace('80%', '50%'))
             return 'linear-gradient(to bottom, %s)' % ', '.join(colors)
         return ''