diff --git a/main.go b/main.go
index ab60858..5677d3e 100644
--- a/main.go
+++ b/main.go
@@ -204,7 +204,7 @@ func (c *RGB) darkerThan(ref RGB, delta uint8) string {
 }
 
 func (c RGB) withAlpha(alpha float64) string {
-	return fmt.Sprintf("#%02x%02x%02x", c.r, c.g, c.b, uint8(255*alpha))
+	return fmt.Sprintf("#%02x%02x%02x%02x", c.r, c.g, c.b, uint8(255*alpha))
 }
 
 func maleAvatar(seed uint64) string {