/* Globo para volver al comienzo */
    .back-to-top {
      position: fixed;
      right: 22px;
      bottom: 22px;
      z-index: 150;
      width: 50px;
      height: 50px;
      border: 2px solid #fff;
      border-radius: 50%;
      background: linear-gradient(135deg, var(--morado), var(--cian));
      color: #fff;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 1.35rem;
      cursor: pointer;
      box-shadow: 0 8px 24px rgba(19,16,98,.3);
      opacity: 0;
      visibility: hidden;
      transform: translateY(10px);
      transition: opacity .25s, visibility .25s, transform .25s;
    }
    .back-to-top.show {
      opacity: 1;
      visibility: visible;
      transform: translateY(0);
    }
    .back-to-top:hover { transform: translateY(-3px); }