body {
  font-family: Arial, sans-serif;
  background-color: #f0f0f0;
  text-align: center;
  margin: 50px;
}

#calculator {
  margin: 0 auto;
  background-color: #fff;
  padding: 20px;
  border-radius: 25px;
  color: black;
	border-width:2px;
	box-shadow: 0 0 70px rgba(0, 0, 0, 0.2);
	  

}

label {
  display: block;
  margin-bottom: 10px;
}

input, select {
  width: 100%;
  padding: 8px;
  margin-bottom: 15px;
  box-sizing: border-box;
	border-width:2px;
}

button {
  background-color: #2980b9;
  color: #fff;
  border: none;
  padding: 10px;
  border-radius: 5px;
  cursor: pointer;
 
  
}

input[readonly] {
  background-color: yellow;
  cursor: not-allowed;
  color:green;
  font-weight:700;
}