.scroll-to-top {
    position: fixed;
    right: 1.25rem;
    bottom: 1.25rem;
    z-index: var(--z-scroll-top);
    width: 44px;
    height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border-color, #ddd);
    border-radius: 50%;
    background: var(--card-bg, #fff);
    color: var(--primary-color, #4481eb);
    box-shadow: 0 4px 16px rgba(15, 23, 42, 0.14);
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(0.5rem);
    transition: opacity 0.2s ease, visibility 0.2s ease, transform 0.2s ease,
        background 0.15s ease, border-color 0.15s ease, color 0.15s ease, box-shadow 0.15s ease;
}

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

.scroll-to-top:hover {
    background: var(--primary-color, #4481eb);
    border-color: var(--primary-color, #4481eb);
    color: #fff;
    box-shadow: 0 6px 20px rgba(68, 129, 235, 0.32);
}

.scroll-to-top:focus-visible {
    outline: 2px solid color-mix(in srgb, var(--primary-color, #4481eb) 55%, transparent);
    outline-offset: 2px;
}

.scroll-to-top__icon {
    display: block;
}

[data-theme="dark"] .scroll-to-top {
    background: var(--card-bg, #2d2d2d);
    border-color: var(--border-color, #444);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.35);
}

@media (max-width: 768px) {
    .scroll-to-top {
        right: 1rem;
        width: 40px;
        height: 40px;
    }
}