/* Updated for full-window and modern design */
html, body {
    height: 100%;
    margin: 0;
    padding: 0;
  }
  body {
    font-family: system-ui, sans-serif;
    background: linear-gradient(135deg, #e0e7ff, #a3bffa);
    display: grid;
    place-items: center;
  }
  .chat-container {
    display: grid;
    grid-template-rows: auto 1fr auto;
    height: 100vh;
    width: 100vw;
    background: white;
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.15);
  }
  .header {
    background: linear-gradient(90deg, #1e3a8a, #4b6cb7);
    color: white;
    padding: 1.5rem;
    text-align: center;
    font-size: 1.75rem;
    font-weight: 700;
  }
  .chat-area {
    flex: 1;
    overflow-y: auto;
    padding: 2rem;
    scroll-behavior: smooth;
  }
  .chat-message {
    max-width: 85%;
    margin-bottom: 1.5rem;
    padding: 1rem 1.5rem;
    border-radius: 1rem;
    font-size: 1rem;
    line-height: 1.6;
  }
  .user-message {
    background: #3b82f6;
    color: white;
    margin-left: auto;
    border-bottom-right-radius: 0.5rem;
  }
  .bot-message {
    background: #f3f4f6;
    color: #1f2937;
    margin-right: auto;
    border-bottom-left-radius: 0.5rem;
  }
  .error-message {
    background: #fee2e2;
    color: #b91c1c;
  }
  .table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1.5rem;
    border: 2px solid #d1d5db;
  }
  .table th, .table td {
    border: 2px solid #d1d5db;
    padding: 0.75rem;
    text-align: left;
    font-size: 1rem;
  }
  .table th {
    background: linear-gradient(90deg, #f3f4f6, #e5e7eb);
    font-weight: 700;
  }
  .input-container {
    padding: 1.5rem;
    display: flex;
    gap: 0.75rem;
    background: #f9fafb;
    border-top: 2px solid #e5e7eb;
  }
  .input-container input {
    flex: 1;
    padding: 1rem;
    border: 2px solid #d1d5db;
    border-radius: 0.75rem;
    font-size: 1rem;
  }
  .input-container button {
    padding: 1rem 2rem;
    border-radius: 0.75rem;
    font-size: 1rem;
    font-weight: 600;
  }
  .send-btn {
    background: linear-gradient(90deg, #3b82f6, #2563eb);
    color: white;
  }
  .send-btn:hover:not(:disabled) {
    background: linear-gradient(90deg, #2563eb, #1d4ed8);
  }
  .clear-btn {
    background: #e5e7eb;
    color: #1f2937;
  }
  .clear-btn:hover:not(:disabled) {
    background: #d1d5db;
  }
  .loading-spinner {
    width: 1.5rem;
    height: 1.5rem;
    border: 3px solid #e5e7eb;
    border-top: 3px solid #3b82f6;
    border-radius: 50%;
    animation: spin 1s linear infinite;
  }
  @keyframes spin {
    to { transform: rotate(360deg); }
  }
  @media (max-width: 640px) {
    .chat-container { height: 92vh; }
    .input-container { flex-direction: column; }
    .input-container input, .input-container button { width: 100%; }
    .table th, .table td { font-size: 0.875rem; padding: 0.5rem; }
  }