body {
    margin: 0;
    font-family: 'Segoe UI', sans-serif;
    background: #f4f7fb;
    color: #333;
  }
  
  header {
    background: #1e3a8a;
    padding: 20px;
    color: white;
  }
  
  nav {
    max-width: 1000px;
    margin: auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
  }
  
  .logo {
    font-size: 24px;
    font-weight: bold;
  }
  
  nav ul {
    list-style: none;
    display: flex;
    gap: 20px;
  }
  
  nav ul li a {
    color: white;
    text-decoration: none;
  }
  
  .hero {
    text-align: center;
    padding: 60px 20px;
    background: linear-gradient(to right, #3b82f6, #2563eb);
    color: white;
  }
  
  .gpa-calculator {
    max-width: 800px;
    margin: auto;
    padding: 30px 20px;
    background: white;
    box-shadow: 0 0 12px rgba(0,0,0,0.05);
    border-radius: 10px;
    margin-top: 30px;
  }
  
  .subject {
    display: flex;
    gap: 10px;
    margin-bottom: 10px;
  }
  
  .subject input, .subject select {
    flex: 1;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 6px;
  }
  
  .buttons {
    margin-top: 10px;
    display: flex;
    gap: 10px;
  }
  
  button {
    padding: 10px 15px;
    background-color: #2563eb;
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-weight: bold;
  }
  
  button:hover {
    background-color: #1d4ed8;
  }
  
  #result {
    font-size: 20px;
    font-weight: bold;
    margin-top: 20px;
    text-align: center;
    color: #111;
  }
  
  footer {
    text-align: center;
    padding: 20px;
    background: #1e3a8a;
    color: white;
    margin-top: 40px;
  }
  
  @media (max-width: 600px) {
    .subject {
      flex-direction: column;
    }
  
    nav ul {
      flex-direction: column;
      align-items: flex-end;
    }
  
    .buttons {
      flex-direction: column;
    }
  }