* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  background: #f5f5f5;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Login Page */
.login-container {
  background: white;
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  width: 100%;
  max-width: 400px;
}

.login-container h1 {
  text-align: center;
  margin-bottom: 1.5rem;
  color: #333;
}

.form-group {
  margin-bottom: 1rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  color: #555;
  font-weight: 500;
}

.form-group input {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid #ddd;
  border-radius: 4px;
  font-size: 1rem;
}

.form-group input:focus {
  outline: none;
  border-color: #007bff;
}

.btn {
  width: 100%;
  padding: 0.75rem;
  background: #007bff;
  color: white;
  border: none;
  border-radius: 4px;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.2s;
}

.btn:hover {
  background: #0056b3;
}

.btn:disabled {
  background: #ccc;
  cursor: not-allowed;
}

.error-message {
  background: #fee;
  color: #c00;
  padding: 0.75rem;
  border-radius: 4px;
  margin-bottom: 1rem;
  display: none;
}

.error-message.visible {
  display: block;
}

/* Chat Page */
.chat-container {
  display: flex;
  flex-direction: column;
  height: 100vh;
  width: 100%;
  max-width: 900px;
  background: white;
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
}

.chat-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 1.5rem;
  background: #007bff;
  color: white;
}

.chat-header h1 {
  font-size: 1.25rem;
}

.header-actions {
  display: flex;
  gap: 0.5rem;
}

.header-btn {
  background: rgba(255, 255, 255, 0.2);
  border: none;
  color: white;
  padding: 0.5rem 1rem;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.875rem;
}

.header-btn:hover {
  background: rgba(255, 255, 255, 0.3);
}

.chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.message {
  max-width: 80%;
  padding: 0.75rem 1rem;
  border-radius: 12px;
  line-height: 1.4;
}

.message.user {
  align-self: flex-end;
  background: #007bff;
  color: white;
}

.message.assistant {
  align-self: flex-start;
  background: #f0f0f0;
  color: #333;
}

.message.system {
  align-self: center;
  background: #fff3cd;
  color: #856404;
  font-size: 0.875rem;
}

.chat-input-container {
  display: flex;
  gap: 0.5rem;
  padding: 1rem 1.5rem;
  border-top: 1px solid #eee;
  background: #fafafa;
}

.chat-input {
  flex: 1;
  padding: 0.75rem 1rem;
  border: 1px solid #ddd;
  border-radius: 24px;
  font-size: 1rem;
  outline: none;
}

.chat-input:focus {
  border-color: #007bff;
}

.send-btn {
  background: #007bff;
  color: white;
  border: none;
  padding: 0.75rem 1.5rem;
  border-radius: 24px;
  cursor: pointer;
  font-size: 1rem;
}

.send-btn:hover {
  background: #0056b3;
}

.send-btn:disabled {
  background: #ccc;
  cursor: not-allowed;
}

.typing-indicator {
  display: none;
  align-self: flex-start;
  padding: 0.75rem 1rem;
  background: #f0f0f0;
  border-radius: 12px;
}

.typing-indicator.visible {
  display: flex;
  gap: 4px;
}

.typing-indicator span {
  width: 8px;
  height: 8px;
  background: #999;
  border-radius: 50%;
  animation: bounce 1.4s infinite ease-in-out;
}

.typing-indicator span:nth-child(1) { animation-delay: 0s; }
.typing-indicator span:nth-child(2) { animation-delay: 0.2s; }
.typing-indicator span:nth-child(3) { animation-delay: 0.4s; }

@keyframes bounce {
  0%, 80%, 100% { transform: translateY(0); }
  40% { transform: translateY(-6px); }
}

/* Responsive */
@media (max-width: 600px) {
  .chat-container {
    max-width: 100%;
  }

  .message {
    max-width: 90%;
  }
}