:root {
  --orange: #f97316;
  --orange-dark: #ea580c;
  --green: #16a34a;
  --ink: #1a1a1a;
  --muted: #6b7280;
  --bg: #f6f6f4;
  --card: #ffffff;
  --line: #e7e5e0;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  font-size: 14px;
  background: var(--bg);
  color: var(--ink);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* 顶栏 */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: #111;
  color: #fff;
  padding: 14px 28px;
}
.brand { display: flex; align-items: center; gap: 14px; }
.logo {
  background: var(--orange);
  color: #fff;
  font-weight: 800;
  padding: 8px 12px;
  border-radius: 8px;
  letter-spacing: 1px;
}
.brand-text h1 { margin: 0; font-size: 17px; }
.brand-text p { margin: 2px 0 0; font-size: 12px; color: #cbd5e1; }
.ghost-btn {
  background: transparent;
  color: #e2e8f0;
  border: 1px solid #475569;
  padding: 6px 13px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 12.5px;
}
.ghost-btn:hover { border-color: var(--orange); color: #fff; }

/* 主体 */
.container { flex: 1; max-width: 860px; width: 100%; margin: 0 auto; padding: 26px 20px 36px; }

.panel {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 26px;
  box-shadow: 0 6px 24px rgba(0,0,0,.04);
}
.panel h2 { margin: 0 0 4px; font-size: 18px; }
.hint { color: var(--muted); margin: 0 0 20px; font-size: 13px; }

/* 两张卡入口 */
.card-row { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.big-card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
  text-align: left;
  padding: 22px 20px;
  border: 2px solid var(--line);
  border-radius: 14px;
  background: #fff;
  cursor: pointer;
  transition: border-color .15s, background .15s;
}
.big-card:hover { border-color: var(--orange); background: #fff7ed; }
.card-tag {
  font-size: 12px;
  font-weight: 700;
  color: #fff;
  background: var(--orange);
  padding: 3px 10px;
  border-radius: 12px;
}
.card-tag.train { background: var(--green); }
.card-name { font-size: 17px; font-weight: 700; }
.card-sub { font-size: 12.5px; font-weight: 600; color: var(--orange-dark); }
.card-desc { font-size: 13px; color: var(--muted); line-height: 1.55; }

/* 三选一 */
.mode-row { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-bottom: 20px; }
.mode-btn {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 5px;
  text-align: left;
  padding: 16px 15px;
  border: 2px solid var(--line);
  border-radius: 12px;
  background: #fff;
  cursor: pointer;
  transition: border-color .15s, background .15s;
}
.mode-btn:hover { border-color: #fca5a5; }
.mode-btn.active { border-color: var(--orange); background: #fff7ed; }
.mode-icon { color: var(--orange); font-weight: 700; font-size: 14px; }
.mode-name { font-size: 14.5px; font-weight: 700; }
.mode-desc { font-size: 12px; color: var(--muted); }

.sub-pane { margin-bottom: 20px; }
.sub-pane label { display: block; font-size: 13px; color: var(--muted); margin-bottom: 8px; }
#caseSelect {
  width: 100%;
  max-width: 460px;
  padding: 10px 12px;
  font-size: 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #fff;
}
.topic-row { display: flex; flex-wrap: wrap; gap: 10px; }
.topic-chip {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
  text-align: left;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  padding: 9px 14px;
  border-radius: 12px;
  cursor: pointer;
  max-width: 300px;
}
.topic-chip:hover { border-color: #9be1b1; }
.topic-chip.active { border-color: var(--green); background: #f0fdf4; }
.chip-label { font-size: 14px; font-weight: 600; }
.topic-chip.active .chip-label { color: var(--green); }
.chip-desc { font-size: 12px; color: var(--muted); }

.primary-btn {
  background: var(--orange);
  color: #fff;
  border: none;
  padding: 11px 20px;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
}
.primary-btn:hover { background: var(--orange-dark); }
.primary-btn:disabled { background: #d1d5db; cursor: not-allowed; }

/* 对话 */
.chat-head { font-size: 13px; color: var(--muted); border-bottom: 1px solid var(--line); padding-bottom: 11px; margin-bottom: 14px; }
.chat-head b { color: var(--ink); }

.messages { display: flex; flex-direction: column; gap: 12px; margin-bottom: 16px; min-height: 180px; max-height: 56vh; overflow-y: auto; padding: 2px; }
.msg { max-width: 88%; padding: 11px 14px; border-radius: 12px; font-size: 13.5px; line-height: 1.6; white-space: normal; }
.msg.user { align-self: flex-end; background: var(--orange); color: #fff; border-bottom-right-radius: 2px; }
.msg.ai { align-self: flex-start; background: #f1f5f9; color: var(--ink); border-bottom-left-radius: 2px; }
.msg.ai p { margin: 0 0 4px; }
.msg.ai p:last-child { margin-bottom: 0; }
.msg.ai h1, .msg.ai h2, .msg.ai h3 { font-size: 14px; margin: 6px 0 3px; }
.msg.ai ul { margin: 4px 0; padding-left: 20px; }
.msg.ai li { margin: 2px 0; }
.msg.ai code { background: #e2e8f0; padding: 1px 5px; border-radius: 4px; font-size: 12.5px; }
.msg .typing { color: var(--muted); font-style: italic; }

.quick-options { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 12px; }
.quick-options[hidden] { display: none; }
.quick-btn {
  font-size: 12.5px;
  font-weight: 500;
  color: var(--green);
  background: #f0fdf4;
  border: 1px solid #bbf7d0;
  padding: 7px 13px;
  border-radius: 18px;
  cursor: pointer;
}
.quick-btn:hover { background: #dcfce7; border-color: var(--green); }

.composer { display: flex; gap: 10px; align-items: flex-end; }
.composer textarea {
  flex: 1;
  resize: vertical;
  padding: 11px 13px;
  font-size: 14px;
  font-family: inherit;
  border: 1px solid var(--line);
  border-radius: 10px;
  line-height: 1.6;
}
.composer textarea:focus { outline: 2px solid #fdba74; border-color: transparent; }

/* 页脚 */
.footer {
  text-align: center;
  color: var(--muted);
  font-size: 12px;
  padding: 16px;
  border-top: 1px solid var(--line);
  background: #fff;
}

@media (max-width: 640px) {
  .card-row, .mode-row { grid-template-columns: 1fr; }
  .topbar { padding: 12px 16px; }
  .brand-text h1 { font-size: 15px; }

  /* 主体：左右边距对称且更紧凑，右侧不留大空白 */
  .container { padding: 18px 14px 28px; }
  .panel { padding: 18px 14px; }
  .panel h2 { font-size: 16px; }

  /* 对话区：气泡贴近两侧、对称留边 */
  .chat-head { font-size: 12px; }
  .messages { gap: 10px; }
  .msg { max-width: 94%; padding: 10px 12px; font-size: 12.5px; }
  .msg.ai h1, .msg.ai h2, .msg.ai h3 { font-size: 13px; }
  .msg.ai code { font-size: 11.5px; }

  /* 发送按钮换行：输入框与按钮纵向堆叠 */
  .composer { flex-direction: column; align-items: stretch; gap: 8px; }
  .composer textarea { font-size: 13px; padding: 10px 12px; }
  .primary-btn { width: 100%; font-size: 13px; padding: 10px; }

  /* 整体字号微降一档 */
  .card-name { font-size: 15px; }
  .card-desc { font-size: 12.5px; }
  .quick-btn { font-size: 12px; }
}