round button css

.btn {
  display:block;
  height: 300px;
  width: 300px;
  border-radius: 50%;
  border: 1px solid red;
  
}  .button {
  background-color: #4CAF50;
  border: none;
  color: white;

    
  padding: 20px;
  text-align: center;
  
  text-decoration: none;
  display: inline-block;
  font-size: 16px;

    margin: 4px 2px;
}

.button1 {border-radius: 2px;}
.button2 
  {border-radius: 4px;}
.button3 {border-radius: 8px;}
.button4 
  {border-radius: 12px;}
.button5 {border-radius: 50%;}