.protocol-tag {
      position: absolute;
      pointer-events: none;
      font-family: 'Consolas', monospace;
      font-weight: 600;
      will-change: transform, opacity;
      animation: floatFade 1.5s ease-out forwards;
      /* 关键修正1：让元素中心对齐鼠标（偏移自身50%） */
      transform: translate(-50%, -50%);
    }

    @keyframes floatFade {
      0% { transform: translate(-50%, -50%) scale(1); opacity: 1; }
      100% { transform: translate(-50%, -110px) scale(0.7); opacity: 0; }
      /* 注意：动画里也要保留 translate(-50%, -50%) 基础偏移 */
    }

    body {
      margin: 0;
      height: 200vh; /* 故意设置长页面，测试滚动后效果 */
      background: #000;
    }