diff --git a/src/checkbox.css b/src/checkbox.css
index 4e04bc5..33e16e8 100644
--- a/src/checkbox.css
+++ b/src/checkbox.css
@@ -30,7 +30,7 @@ label.cbox > input + *::before {
 	border-radius: 50%;
 	aspect-ratio: 1 / 1;
 	border: var(--synergy-border-width) solid var(--synergy-border);
-	transition: background .1s, box-shadow .2s;
+	transition: background .1s, box-shadow .2s, border-color .1s;
 	background: var(--synergy-bg);
 	box-shadow: 0 1px 2px 0 rgba(0, 0, 0, .1);
 	grid-area: box;
@@ -38,6 +38,7 @@ label.cbox > input + *::before {
 
 label.cbox > input:checked + *::before {
 	background: var(--synergy-border-active);
+	border-color: transparent;
 }
 
 label.cbox > input:focus-visible  + *::before {