border radius of input button code example

Example 1: round button css

.btn {
  display:block;
  height: 300px;
  width: 300px;
  border-radius: 50%;
  border: 1px solid red;
  
}

Example 2: how to round the corners of a div outline in css

div {
  outline: auto;
  outline-style: round;
}