/* 全站回到顶部悬浮按钮（seemb4 / seemb6 共用） */
.site-back-to-top {
    position: fixed;
    right: 18px;
    bottom: 28px;
    z-index: 10008;
    width: 48px;
    height: 48px;
    margin: 0;
    padding: 0;
    border: none;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: #fff;
    background: linear-gradient(
        145deg,
        var(--cat-primary, #4267b2) 0%,
        color-mix(in srgb, var(--cat-primary, #4267b2) 72%, #1a2d52 28%) 100%
    );
    box-shadow:
        0 8px 22px color-mix(in srgb, var(--cat-primary, #4267b2) 38%, transparent),
        0 2px 8px rgba(15, 23, 42, 0.14);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(14px) scale(0.9);
    transition:
        opacity 0.28s ease,
        transform 0.28s ease,
        visibility 0.28s ease,
        box-shadow 0.22s ease,
        background 0.22s ease;
}

.site-back-to-top.is-visible {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateY(0) scale(1);
}

.site-back-to-top:hover {
    box-shadow:
        0 10px 28px color-mix(in srgb, var(--cat-primary, #4267b2) 48%, transparent),
        0 4px 12px rgba(15, 23, 42, 0.18);
}

.site-back-to-top:active {
    transform: translateY(1px) scale(0.97);
}

.site-back-to-top.is-visible:active {
    transform: translateY(1px) scale(0.97);
}

.site-back-to-top:focus-visible {
    outline: 2px solid var(--cat-primary, #4267b2);
    outline-offset: 3px;
}

.site-back-to-top__icon {
    display: flex;
    align-items: center;
    justify-content: center;
    line-height: 0;
}

.site-back-to-top__icon svg {
    display: block;
    width: 22px;
    height: 22px;
}

/* 手机端右侧有客服悬浮条时，按钮左移避免重叠 */
@media (max-width: 991.98px) {
    html[data-mobile-show-sidebar="1"] .site-back-to-top {
        right: 54px;
        bottom: 22px;
        width: 44px;
        height: 44px;
    }
}

@media (max-width: 575.98px) {
    .site-back-to-top {
        right: 14px;
        bottom: 18px;
        width: 44px;
        height: 44px;
    }

    html[data-mobile-show-sidebar="1"] .site-back-to-top {
        right: 50px;
        bottom: 16px;
    }
}