body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background-color: #f0f0f0;
  margin: 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  padding: 20px;
  box-sizing: border-box;
}

header {
  text-align: center;
  margin-bottom: 20px;
}

.calculator-container {
  background-color: #fff;
  padding: 30px;
  border-radius: 8px;
  box-shadow: 0 0 15px rgba(0, 0, 0, 0.2);
  max-width: 600px;
  width: 100%;
  text-align: center;
}

h1 {
  color: #3498db;
  margin: 0;
}

label {
  display: block;
  margin-top: 10px;
  margin-bottom: 5px;
  color: #2c3e50;
  text-align: left;
}

input, select {
  width: 100%;
  padding: 8px;
  margin-bottom: 10px;
  border: 1px solid #ccc;
  border-radius: 4px;
  box-sizing: border-box;
}

button {
  padding: 10px 20px;
  background-color: #3498db;
  color: #fff;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  margin: 5px;
}

button:hover {
  background-color: #2980b9;
}

#result-container {
  margin-top: 20px;
  text-align: left;
}

span {
  font-weight: bold;
  color: #e74c3c;
}

p {
  margin: 5px 0;
}

/* Media queries for better responsiveness */
@media (max-width: 480px) {
  .calculator-container {
    padding: 20px;
  }
  button {
    width: 100%;
    margin: 10px 0;
  }
}