/* === Scroll-to-top button === */
    #scrollTopBtn {
      position: fixed;
      right: 40px;
      bottom: 40px;
      z-index: 1000;
      background: var(--light-moss);
      color: var(--rifle-green);
      border: none;
      border-radius: 50%;
      width: 60px;
      height: 60px;
      font-size: 1.4rem;
      display: flex;
      align-items: center;
      justify-content: center;
      box-shadow: 0 5px 20px rgba(0,0,0,0.15);
      cursor: pointer;
      transition: var(--transition);
      opacity: 0;
      visibility: hidden;
      transform: translateY(30px);
    }

    #scrollTopBtn.show {
      opacity: 1;
      visibility: visible;
      transform: translateY(0);
    }

    #scrollTopBtn:hover {
      transform: translateY(-8px) rotate(5deg);
      box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    }