#backToTopBtn {
    position: fixed;
    inset-inline-end: 1.25rem;
    bottom: calc(env(safe-area-inset-bottom, 0px) + 5.75rem);
    z-index: 40;
    height: 44px; padding: 0 16px;
    display: inline-flex; align-items: center; gap: 8px;
    border: 1px solid var(--rule);
    border-radius: 999px;
    background: var(--paper-2);
    color: var(--theme-600, var(--ink));
    font-family: 'Inter', system-ui, sans-serif;
    font-size: 13px; font-weight: 600;
    box-shadow: var(--shadow-md, 0 4px 12px rgba(0,0,0,.1));
    cursor: pointer;
    opacity: 0; visibility: hidden; transform: translateY(12px);
    transition: opacity .26s ease, transform .26s ease, visibility .26s ease,
                background .18s ease, color .18s ease, border-color .18s ease, box-shadow .18s ease;
  }
  #backToTopBtn.is-visible { opacity: 1; visibility: visible; transform: translateY(0); }
  #backToTopBtn .fas { font-size: 14px; }
  #backToTopBtn .cl-b2t-label { line-height: 1; }
  #backToTopBtn:hover {
    transform: translateY(-3px);
    background: var(--theme-600, var(--ink));
    border-color: var(--theme-600, var(--ink));
    color: #fff;
    box-shadow: 0 10px 24px -8px rgba(0,0,0,.28);
  }
  #backToTopBtn:active { transform: translateY(-1px); }
  @media (min-width: 1024px) {
    #backToTopBtn { bottom: 1.75rem; inset-inline-end: 1.75rem; }
  }