:root {
  --bg: #f8fafc;
  --card: #fff;
  --muted: #6b7280;
  --border: #e5e7eb;
  --ink: #111827;
}
* {
  box-sizing: border-box;
}
body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
}
.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 20px;
}
h1 {
  margin: 0 0 10px;
  font-size: 22px;
}
#chat {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px;
}
.messages {
  height: 420px;
  overflow: auto;
  padding: 8px;
}
.msg {
  max-width: 85%;
  padding: 10px 12px;
  margin: 6px 0;
  border-radius: 10px;
  white-space: pre-wrap;
}
.user {
  background: #e0f2fe;
  margin-left: auto;
}
.bot {
  background: #eef2ff;
  margin-right: auto;
}
.chat-form {
  display: flex;
  gap: 8px;
  margin-top: 10px;
}
.chat-form input[type="text"] {
  flex: 1;
  padding: 10px 12px;
  border: 1px solid #d1d5db;
  border-radius: 10px;
}
.chat-form button {
  padding: 10px 14px;
  border: 0;
  border-radius: 10px;
  background: #111827;
  color: #fff;
  cursor: pointer;
}