body {
    font-family: Arial, sans-serif;
    margin: 0;
    background: #f4f4f4;
    color: #333;
  }
  
  header {
    background: #222;
    color: white;
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
  }
  
  nav button {
    background: #444;
    color: white;
    border: none;
    margin: 0.3rem;
    padding: 0.5rem 1rem;
    cursor: pointer;
    border-radius: 4px;
  }
  
  main {
    padding: 2rem;
  }
  
  .tela {
    display: none;
    background: white;
    padding: 2rem;
    margin: 1rem 0;
    border-radius: 8px;
  }
  
  .ativa {
    display: block;
  }
  
  .grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
    margin-top: 1rem;
  }
  
  .grid div {
    background: #eee;
    padding: 1rem;
    border-radius: 6px;
    text-align: center;
  }
  
  form {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    max-width: 400px;
  }
  
  input, textarea {
    padding: 0.7rem;
    border: 1px solid #ccc;
    border-radius: 4px;
  }
  
  button[type="submit"], button {
    background: #0077cc;
    color: white;
    border: none;
    padding: 0.7rem;
    cursor: pointer;
    border-radius: 4px;
  }
  
  footer {
    text-align: center;
    padding: 1rem;
    background: #222;
    color: white;
  }