body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background: #f9f9f9;
  color: #333;
  line-height: 1.6;
}

header {
  background: #4a6fa5;
  color: white;
  padding: 20px;
  text-align: center;
}

main {
  max-width: 800px;
  margin: auto;
  padding: 20px;
}

.calculator {
  background: white;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  margin-bottom: 20px;
}

label {
  display: block;
  margin: 10px 0 5px;
}

input {
  width: 100%;
  padding: 8px;
  margin-bottom: 15px;
}

button {
  background: #4a6fa5;
  color: white;
  padding: 10px 15px;
  border: none;
  cursor: pointer;
  border-radius: 4px;
}

button:hover {
  background: #3b5a85;
}

.result {
  margin-top: 15px;
  padding: 15px;
  background: #e7f4e4;
  border-left: 4px solid #4caf50;
}

h2 {
  margin-top: 40px;
}

footer {
  text-align: center;
  padding: 15px;
  font-size: 14px;
  color: #777;
}