body {
  font-family: Arial, sans-serif;
  background: #0f172a;
  color: #f8fafc;
  margin: 0;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 2rem;
}

.card {
  background: #1e293b;
  border-radius: 14px;
  padding: 1rem;
  margin-bottom: 1rem;
}

.chat-box {
  min-height: 320px;
  max-height: 420px;
  overflow-y: auto;
}

.message {
  margin-bottom: 0.75rem;
  padding: 0.75rem;
  border-radius: 10px;
}

.user {
  background: #334155;
}

.assistant {
  background: #475569;
}

.input-row {
  display: flex;
  gap: 0.5rem;
}

input, button {
  padding: 0.75rem;
  border-radius: 10px;
  border: none;
}

input {
  flex: 1;
}