/* Hacker vibe button */
  #backToTop {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background-color: #0d0d0d;           /* Dark background */
    color: #00ff00;                        /* Neon green text */
    border: 2px solid #00ff00;            /* Neon border */
    padding: 15px 20px;
    font-size: 18px;
    font-family: 'Courier New', Courier, monospace; /* Hacker font */
    font-weight: bold;
    border-radius: 10px;
    cursor: pointer;
    box-shadow: 0 0 10px #00ff00, 0 0 20px #00ff00;
    transition: all 0.3s ease;
    opacity: 0;
    visibility: hidden;
    z-index: 1000;
  }

  #backToTop:hover {
    transform: translateY(-3px);
    box-shadow: 0 0 20px #00ff00, 0 0 40px #00ff00;
    text-shadow: 0 0 5px #00ff00, 0 0 10px #00ff00;
    background-color: #001100;
  }

  @media (max-width: 600px) {
    #backToTop {
      bottom: 20px;
      right: 20px;
      padding: 12px 16px;
      font-size: 16px;
    }
  }