.back-to-top {
    position: fixed;
    bottom: 24px;
    right: 24px;
    z-index: 9999;
    width: 52px;
    height: 52px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: none;
    border-radius: 50%;
    color: #fff;
    cursor: pointer;
    background: linear-gradient(135deg, #6d3bff, #ff3f86);
    box-shadow: 0 10px 24px rgba(109, 59, 255, 0.34);
    opacity: 0;
    visibility: hidden;
    transform: translateY(12px);
    transition: opacity .25s ease, transform .25s ease, box-shadow .25s ease;
}

.back-to-top.is-visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    transform: translateY(-3px);
    box-shadow: 0 14px 30px rgba(109, 59, 255, 0.44);
}

@media (max-width: 768px) {
    .back-to-top {
        bottom: 16px;
        right: 16px;
        width: 46px;
        height: 46px;
    }
}