body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background: #f7f9fc;
    color: #333;
  }
  .header {
    text-align: center;
    background: #0077ff;
    color: #fff;
    padding: 20px;
  }
  .content {
    display: flex;
    justify-content: center;
    padding: 30px;
  }
  .calculator {
    background: #fff;
    padding: 20px;
    border-radius: 12px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
    width: 350px;
  }
  .calculator h2 {
    margin-bottom: 15px;
  }
  .calculator label {
    display: block;
    margin: 10px 0 5px;
  }
  .calculator input {
    width: 100%;
    padding: 8px;
    border: 1px solid #ccc;
    border-radius: 6px;
  }
  .calculator button {
    margin-top: 15px;
    padding: 10px;
    width: 100%;
    background: #0077ff;
    color: #fff;
    border: none;
    border-radius: 6px;
    cursor: pointer;
  }
  .calculator button:hover {
    background: #005ec2;
  }
  #result {
    margin-top: 20px;
    font-weight: bold;
    color: #0077ff;
  }
  .footer {
    text-align: center;
    padding: 15px;
    background: #222;
    color: #aaa;
  }