body {
  font-family: Arial, sans-serif;
  background: #f4f6f8;
  margin: 0;
  padding: 0;
}

header {
  background: #0a58ca;
  color: white;
  padding: 20px;
  text-align: center;
}

.calculator-box {
  background: white;
  max-width: 400px;
  margin: 20px auto;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

.calculator-box label {
  display: block;
  margin-top: 10px;
}

.calculator-box input {
  width: 100%;
  padding: 10px;
  margin-top: 5px;
}

button {
  width: 100%;
  margin-top: 15px;
  padding: 12px;
  background: #0a58ca;
  color: white;
  border: none;
  cursor: pointer;
  font-size: 16px;
}

button:hover {
  background: #084298;
}

.result {
  margin-top: 20px;
  background: #eef3ff;
  padding: 10px;
  border-radius: 5px;
}

.content {
  max-width: 800px;
  margin: 20px auto;
  background: white;
  padding: 20px;
}

footer {
  text-align: center;
  padding: 15px;
  background: #222;
  color: #ccc;
}