.scroll-to-top {
    position: fixed;
    right: 24px;
    bottom: 24px;
    z-index: 1050;
    width: 48px;
    height: 48px;
    display: grid;
    place-items: center;
    border: 1px solid #052f8a;
    border-radius: 50%;
    background: var(--blue);
    color: #fff;
    box-shadow: 0 8px 22px rgba(20, 33, 61, .28);
    opacity: 0;
    visibility: hidden;
    transform: translateY(12px);
    transition: opacity .2s ease, transform .2s ease, visibility .2s ease, background-color .2s ease;
}
.scroll-to-top.is-visible { opacity: 1; visibility: visible; transform: translateY(0); }
.scroll-to-top:hover,
.scroll-to-top:focus-visible { background: var(--green); border-color: #087429; color: #fff; }
.scroll-to-top:focus-visible { outline: 3px solid rgba(6, 63, 184, .3); outline-offset: 3px; }
@media (max-width: 576px) {
    .scroll-to-top { right: 16px; bottom: 16px; width: 44px; height: 44px; }
}
@media (prefers-reduced-motion: reduce) {
    .scroll-to-top { transition: none; }
}