/* 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 rgba(60, 60, 67, 0.16);
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.55);
    color: var(--sp-ink, #1d1d1f);
    box-shadow:
        0 14px 36px rgba(13, 21, 32, 0.14),
        inset 0 1px 0 rgba(255, 255, 255, 0.5);
    backdrop-filter: blur(22px) saturate(130%);
    -webkit-backdrop-filter: blur(22px) saturate(130%);
    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: rgba(68, 93, 239, 0.5);
    color: var(--sp-accent-deep, #2f40c2);
    box-shadow:
        0 18px 40px rgba(13, 21, 32, 0.16),
        inset 0 1px 0 rgba(255, 255, 255, 0.55);
    transform: translate3d(0, -2px, 0) scale(1.04);
}

.sp-back-top:focus-visible {
    outline: 2px solid var(--sp-accent, #445def);
    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: rgba(28, 30, 36, 0.55);
    border-color: rgba(255, 255, 255, 0.16);
    color: rgba(255, 255, 255, 0.92);
    box-shadow:
        0 16px 40px rgba(0, 0, 0, 0.4),
        inset 0 1px 0 rgba(255, 255, 255, 0.08);
}

:root[data-theme="dark"] .sp-back-top:hover {
    border-color: rgba(68, 93, 239, 0.5);
    color: var(--sp-accent-deep, #5e7eff);
}

@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;
    }
}