/* ===== 空会话欢迎态 WelcomeHero（Leader 2026-09-22） =====
 * 宿主证据：main-b1WagHab.js `function WelcomeHero({greeting, illustrationSrc})`
 *   → <div class="welcome-hero"><img class="welcome-hero__illustration" width=240><h1 class="welcome-hero__greeting">
 * 文案：i18n emptyState.prompt = "{{displayName}}，今天你想推进什么？"（无名时 promptWithoutName）
 * 样式：dtcoder-glass-react.css .welcome-hero{flex column center gap 20px}
 *   .welcome-hero__illustration{width:240px;height:auto;user-select:none;pointer-events:none}
 *   .welcome-hero__greeting{font-size:var(--font-size-2xl)=24px;font-weight:600;line-height:normal;text-align:center;color:var(--foreground)}
 * 实拍：ref/host-empty-state.png（2x）插图带 y336–585、标题 y636–684，整体在 transcript 内垂直居中偏上
 * 显隐：仅 #thread 为空时显示（CSS :empty，不依赖 JS）；thread 模块写入任何子节点即自动隐藏。
 */
.thread:empty { display: none; }
.thread:empty + .welcome-hero,
.welcome-hero { display: none; }
.transcript:has(> .thread:empty) > .welcome-hero {
  display: flex; flex-direction: column; align-items: center; gap: 20px;
  position: absolute; left: 0; right: 0;
  top: 50%; transform: translateY(-64%);
  padding: 0 24px;
  pointer-events: auto;
}
.transcript { position: relative; }
.welcome-hero__illustration {
  display: block; flex-shrink: 0;
  width: min(300px, 100%); height: auto;
  user-select: none; pointer-events: none;
}
.welcome-hero__greeting {
  margin: 0;
  font-family: inherit;
  font-size: var(--am-font-size-2xl, 24px);
  font-weight: var(--am-font-weight-semibold, 600);
  line-height: normal;
  text-align: center;
  color: var(--text);
}
.welcome-actions { display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; margin-top: 4px; }
.welcome-actions a { display: inline-flex; align-items: center; gap: 18px; padding: 10px 14px; border: 1px solid #e9e5ee; border-radius: 10px; color: #686173; background: #fff; font-size: var(--type-caption-size); text-decoration: none; transition: background .15s, border-color .15s;  line-height: var(--type-caption-line); }
.welcome-actions a span { color: #9a86b9; }
.welcome-actions a:hover { background: #f6f2fb; border-color: #cbb8e5; }
.welcome-actions a:focus-visible { outline: 2px solid #8050c8; outline-offset: 3px; }
@media (max-width: 720px) {
  .welcome-hero__illustration { width: min(240px, 60vw, 100%); }
  .welcome-hero__greeting { font-size: var(--am-font-size-xl, 20px); }
}
@media (max-height: 700px) {
  .welcome-hero__illustration { width: min(220px, 100%); }
}