/* 轻量传播页公共壳样式（_promo-head/_promo-foot；会议主题主页 + AI 服务组合说明页共用）
 * 气质：稳重、大气、留白充分；主色深墨蓝-灰（非科技紫蓝），点缀暖金 #b8860b。
 * 不做渐变球、光斑、玻璃拟态；卡片圆角 ≤8px。
 */
:root {
  --pm-ink: #1f2a37;
  --pm-ink-soft: #5b6b7c;
  --pm-line: #e4e8ee;
  --pm-bg: #f5f6f8;
  --pm-card: #ffffff;
  --pm-brand: #0f2740;
  --pm-accent: #b8860b;
  --pm-radius: 8px;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--pm-ink);
  background: var(--pm-bg);
  font-size: 15px;
  line-height: 1.7;
}
img { max-width: 100%; }
a { color: inherit; }
button { font-family: inherit; cursor: pointer; }

/* ---- 极简品牌条 ---- */
.promo-bar {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .96);
  border-bottom: 1px solid var(--pm-line);
  backdrop-filter: saturate(1.2);
}
.promo-bar-inner {
  width: min(1180px, calc(100% - 40px));
  margin: 0 auto;
  height: 52px;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
}
.promo-bar-brand {
  font-weight: 600; font-size: 14px; color: var(--pm-brand);
  text-decoration: none; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.promo-bar-cap { font-size: 12.5px; color: var(--pm-accent); white-space: nowrap; }

/* ---- 主内容宽度收口 ---- */
.promo-main { width: 100%; }

/* ---- 异常状态（404/503） ---- */
.promo-state {
  width: min(680px, calc(100% - 40px));
  margin: 96px auto 128px;
  background: var(--pm-card);
  border: 1px solid var(--pm-line);
  border-radius: var(--pm-radius);
  padding: 48px 32px;
  text-align: center;
}
.promo-state b { display: block; font-size: 19px; margin-bottom: 8px; }
.promo-state span { display: block; color: var(--pm-ink-soft); font-size: 14px; margin-bottom: 20px; }
.promo-btn {
  display: inline-block; padding: 9px 22px; border-radius: 6px; font-size: 14px;
  text-decoration: none; border: 1px solid var(--pm-line); background: #fff; color: var(--pm-ink);
}
.promo-btn-primary { background: var(--pm-brand); border-color: var(--pm-brand); color: #fff; }

/* ---- 页脚 ---- */
.promo-footer { margin-top: 64px; background: var(--pm-brand); color: #9fb0c3; font-size: 13px; padding: 30px 0 24px; }
.promo-footer-inner { width: min(1180px, calc(100% - 40px)); margin: 0 auto; }
.promo-footer-brand b { color: #fff; font-size: 15px; margin-right: 10px; }
.promo-footer-brand span { font-size: 12px; }
.promo-footer-links { display: flex; flex-wrap: wrap; gap: 16px; margin: 12px 0; }
.promo-footer-links a { color: #c3cfdd; text-decoration: none; }
.promo-footer-links a:hover { color: #fcd34d; }
.promo-footer-copy { font-size: 12px; color: #68809a; }
.promo-footer-copy a { color: #68809a; text-decoration: none; }

/* ---- 轻提示 toast ---- */
.toast {
  position: fixed; left: 50%; bottom: 96px; transform: translateX(-50%) translateY(8px);
  background: rgba(23, 32, 42, .92); color: #fff; font-size: 13.5px;
  padding: 10px 18px; border-radius: 6px; max-width: min(520px, calc(100vw - 48px));
  opacity: 0; pointer-events: none; transition: opacity .22s ease, transform .22s ease; z-index: 200;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ---- 动效尊重系统设置 ---- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none !important; animation: none !important; scroll-behavior: auto !important; }
}

/* ---- 移动端 ---- */
@media (max-width: 640px) {
  .promo-bar-inner { width: calc(100% - 28px); height: 48px; }
  .promo-bar-brand { max-width: 60vw; }
  .promo-footer-inner { width: calc(100% - 28px); }
}