diff --git a/src/button-card.ts b/src/button-card.ts
index ef2dca9..10fddc2 100644
--- a/src/button-card.ts
+++ b/src/button-card.ts
@@ -669,6 +669,7 @@ class ButtonCard extends LitElement {
     const blankCardStyle = {
       background: 'none',
       'box-shadow': 'none',
+      'border-style': 'none',
       ...cardStyle,
     };
     return html`