/* Search Studio: floating back-to-top control. */

.sp-back-top {
    position: fixed;
    right: max(16px, env(safe-area-inset-right, 0px) + 16px);
    bottom: max(20px, env(safe-area-inset-bottom, 0px) + 20px);
    z-index: 160;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    padding: 0;
    border: 1px solid var(--sp-line-strong, rgba(14, 26, 44, 0.18));
    border-radius: 0;
    background: var(--sp-surface, #ffffff);
    color: var(--sp-ink, #1d1d1f);
    box-shadow: none;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translate3d(0, 28px, 0) scale(0.55);
    transition:
        opacity 0.42s cubic-bezier(0.22, 1, 0.36, 1),
        transform 0.52s cubic-bezier(0.16, 1.2, 0.3, 1),
        visibility 0.42s step-end,
        border-color 0.2s ease,
        color 0.2s ease,
        box-shadow 0.2s ease;
}

.sp-back-top.is-visible {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translate3d(0, 0, 0) scale(1);
    transition:
        opacity 0.42s cubic-bezier(0.22, 1, 0.36, 1),
        transform 0.55s cubic-bezier(0.16, 1.25, 0.3, 1),
        visibility 0s linear,
        border-color 0.2s ease,
        color 0.2s ease,
        box-shadow 0.2s ease;
}

.sp-back-top:hover {
    border-color: var(--sp-accent);
    color: var(--sp-accent-deep);
    box-shadow: none;
    transform: translate3d(0, -2px, 0) scale(1.04);
}

.sp-back-top:focus-visible {
    outline: 2px solid var(--sp-accent);
    outline-offset: 3px;
}

.sp-back-top:active {
    transform: translate3d(0, 0, 0) scale(0.96);
}

.sp-back-top svg {
    display: block;
}

:root[data-theme="dark"] .sp-back-top {
    background: var(--sp-surface);
    border-color: var(--sp-line-strong);
    color: var(--sp-ink);
    box-shadow: none;
}

:root[data-theme="dark"] .sp-back-top:hover {
    border-color: var(--sp-accent);
    color: var(--sp-accent-deep);
}

@media (prefers-reduced-motion: reduce) {
    .sp-back-top,
    .sp-back-top.is-visible,
    .sp-back-top:hover,
    .sp-back-top:active {
        transition-duration: 0.01ms;
        transform: none;
    }
}