body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #f4f7fb;
  color: #1f2937;
}

.container {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
}

.card {
  width: 100%;
  max-width: 800px;
  background: white;
  border-radius: 16px;
  padding: 24px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
}

.topbar {
  margin-bottom: 12px;
}

.back-link {
  color: #2563eb;
  text-decoration: none;
  font-size: 14px;
}

h1 {
  margin-top: 0;
  margin-bottom: 8px;
}

.subtitle {
  color: #6b7280;
  margin-bottom: 20px;
}

.messages {
  height: 420px;
  overflow-y: auto;
  background: #f9fafb;
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 16px;
  border: 1px solid #e5e7eb;
}

.message {
  max-width: 75%;
  padding: 12px 14px;
  border-radius: 14px;
  margin-bottom: 12px;
  line-height: 1.5;
  white-space: pre-wrap;
}

.message.user {
  background: #2563eb;
  color: white;
  margin-left: auto;
}

.message.assistant {
  background: #e5e7eb;
  color: #111827;
  margin-right: auto;
}

.chat-form {
  display: flex;
  gap: 10px;
}

.chat-form input {
  flex: 1;
  padding: 14px;
  border-radius: 10px;
  border: 1px solid #d1d5db;
  font-size: 15px;
}

.chat-form button,
.chat-actions button {
  padding: 14px 18px;
  border: none;
  border-radius: 10px;
  background: #2563eb;
  color: white;
  cursor: pointer;
  font-size: 15px;
}

.chat-form button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.chat-actions {
  margin-top: 12px;
}