/* 首页漂浮广告：学院公众号二维码卡片。
   默认停在右下角，脚本接管后整屏缓慢漂移；层级低于头部视觉（40）与公众号弹层（60），
   高于正文；窄屏与打印不显示。只在首页引入。 */
.float-ad {
  position: fixed;
  z-index: 35;
  right: 24px;
  bottom: 24px;
  width: 168px;
  padding: 14px 12px 12px;
  border: 1px solid #ece4e1;
  border-radius: 4px;
  background: #fff;
  box-shadow: 0 14px 34px rgb(23 23 23 / 18%);
  text-align: center;
  animation: float-ad-in 0.42s cubic-bezier(0.2, 0.7, 0.2, 1) both;
}
/* 漂移状态：定位交给 transform，入场动画只动透明度，两者不抢 transform。 */
.float-ad.is-drifting {
  top: 0;
  right: auto;
  bottom: auto;
  left: 0;
  will-change: transform;
}
.float-ad::before {
  content: "";
  position: absolute;
  inset: 0 0 auto;
  height: 4px;
  border-radius: 4px 4px 0 0;
  background: var(--college-red);
}
.float-ad-qr {
  display: block;
  width: 132px;
  height: 132px;
  margin: 4px auto 8px;
  border: 1px solid #f0ebe8;
}
.float-ad p {
  margin: 0;
  color: var(--college-ink);
  font-size: 13px;
  line-height: 1.6;
}
.float-ad p strong {
  display: block;
  color: var(--college-red);
  font-size: 15px;
  letter-spacing: 1px;
}
.float-ad-close {
  position: absolute;
  top: -10px;
  right: -10px;
  display: grid;
  place-items: center;
  width: 24px;
  height: 24px;
  border: 1px solid #e0d5d2;
  border-radius: 50%;
  background: #fff;
  color: #777;
  font-size: 12px;
  cursor: pointer;
  box-shadow: 0 2px 8px rgb(0 0 0 / 12%);
}
.float-ad-close:hover,
.float-ad-close:focus-visible {
  border-color: var(--college-red);
  color: var(--college-red);
}
@keyframes float-ad-in {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}
@media (max-width: 1023px) {
  .float-ad {
    display: none;
  }
}
@media (prefers-reduced-motion: reduce) {
  .float-ad {
    animation: none;
  }
}
@media print {
  .float-ad {
    display: none;
  }
}