:root {
  --bg: #eef3fb;
  --card: #ffffff;
  --text: #0f172a;
  --sub: #64748b;
  --brand: #1368db;
  --bubble-user: #1368db;
  --bubble-bot: #f8fafc;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: radial-gradient(circle at top left, #ddeafe 0%, var(--bg) 40%);
  font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
}

.wrap {
  width: min(900px, 94vw);
  margin: 20px auto;
  display: grid;
  gap: 12px;
}

.card {
  background: var(--card);
  border-radius: 14px;
  padding: 16px;
  box-shadow: 0 10px 24px rgba(30, 64, 120, 0.08);
}

.hero h1 { margin: 0; font-size: 28px; }
.hero p { margin: 8px 0 0; color: var(--sub); }

.messages {
  height: 56vh;
  min-height: 360px;
  overflow: auto;
  padding: 8px;
  background: #f4f7fb;
  border-radius: 12px;
}

.msg {
  max-width: 85%;
  margin: 8px 0;
  padding: 10px 12px;
  border-radius: 12px;
  white-space: pre-wrap;
  line-height: 1.6;
}

.msg.user {
  margin-left: auto;
  background: var(--bubble-user);
  color: #fff;
}

.msg.bot {
  margin-right: auto;
  background: var(--bubble-bot);
  color: var(--text);
  border: 1px solid #e5e7eb;
}

.quick-row {
  margin-top: 12px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.quick {
  border: 0;
  border-radius: 999px;
  padding: 8px 12px;
  background: #e8f1ff;
  color: var(--brand);
  cursor: pointer;
}

.input-row {
  margin-top: 12px;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
}

textarea {
  width: 100%;
  min-height: 88px;
  border-radius: 10px;
  border: 1px solid #d5dbe5;
  padding: 10px;
  font-size: 15px;
}

#sendBtn {
  align-self: end;
  border: 0;
  border-radius: 10px;
  background: var(--brand);
  color: #fff;
  padding: 10px 16px;
  cursor: pointer;
}