Why #Mouse does not receive border-radius?

Question

https://code.sololearn.com/WG2D6QvWTT06/?ref=app

Answer 1

#Mouse{
border-radius:50%;
}

You miss a semicolon ; after 50%

Answer 2

You are welcome. Nice code 👍👍

Answer 3

Thank you)) . Mindfulness and accuracy is not mine)))