* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  body {
    font-family: 'Arial', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    color: #333;
    position: relative;
  }
  
  body::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url('img/darmajaya.jpg'); /* Gambar background */
    background-size: cover;
    background-position: center;
    opacity: 0.5; /* Transparansi background */
    z-index: -1; /* Membuat lapisan ini di bawah elemen lain */
  }
  
  .container {
    background-color: rgba(255, 255, 255, 0.85); /* Warna putih dengan transparansi */
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 0 30px rgba(0, 0, 0, 0.15);
    width: 100%;
    max-width: 600px;
    z-index: 1; /* Pastikan kontainer berada di atas lapisan background */
  }
  
  header {
    text-align: center;
    margin-bottom: 40px;
  }
  
  header h1 {
    font-size: 2.4rem;
    color: #2c3e50;
  }
  
  header p {
    font-size: 1rem;
    color: #7f8c8d;
  }
  
  form {
    margin-bottom: 30px;
  }
  
  .form-group {
    margin-bottom: 20px;
  }
  
  .form-group label {
    display: block;
    font-weight: bold;
    margin-bottom: 5px;
    color: #2c3e50;
  }
  
  .form-group input,
  .form-group textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid #bdc3c7;
    border-radius: 8px;
    font-size: 1rem;
    outline: none;
    transition: border-color 0.3s ease;
  }
  
  .form-group input:focus,
  .form-group textarea:focus {
    border-color: #2980b9;
  }
  
  .form-group textarea {
    resize: vertical;
    min-height: 100px;
  }
  
  .btn {
    background-color: #3498db;
    color: #fff;
    padding: 12px 15px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    width: 100%;
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
  }
  
  .btn:hover {
    background-color: #2980b9;
    box-shadow: 0 5px 15px rgba(41, 128, 185, 0.4);
  }
  
  .guest-list-link {
    text-align: center;
    margin-top: 20px;
  }
  
  .guest-list-link a {
    color: #3498db;
    text-decoration: none;
    transition: color 0.3s ease;
  }
  
  .guest-list-link a:hover {
    text-decoration: underline;
    color: #2980b9;
  }
  
  @media (max-width: 600px) {
    header h1 {
        font-size: 1.8rem;
    }
  
    header p {
        font-size: 0.9rem;
    }
  
    .btn {
        font-size: 0.9rem;
    }
  }
  
  /* CSS halaman daftar-tamu */
  /* Tambahan untuk tabel DataTables */
  table.dataTable {
    border-collapse: collapse;
    width: 100%;
    margin: 20px 0;
  }
  
  table.dataTable thead th {
    background-color: #3498db;
    color: white;
    font-weight: bold;
    text-align: left;
    padding: 12px;
  }
  
  table.dataTable tbody td {
    padding: 10px;
    border-bottom: 1px solid #ddd;
  }
  
  table.dataTable tbody tr:nth-child(even) {
    background-color: #f9f9f9;
  }
  
  .btn-back {
    display: inline-block;
    margin-top: 20px;
    padding: 10px 15px;
    background-color: #3498db;
    color: white;
    text-decoration: none;
    border-radius: 5px;
  }
  
  .btn-back:hover {
    background-color: #2980b9;
  }
  
  /* CSS untuk alert */
  .alert {
    padding: 15px;
    margin: 15px 0;
    border-radius: 5px;
    font-size: 1rem;
    color: #155724; /* Teks warna hijau gelap */
  }
  
  .alert-success {
    background-color: #d4edda; /* Latar belakang hijau muda */
    border: 1px solid #c3e6cb; /* Garis border hijau muda */
    color: #155724; /* Teks warna hijau gelap */
  }
  
  .alert.hidden {
    display: none;
  }