.back-to-top__button {
    position: fixed;
    bottom: 70px;
    right: 50px;
    z-index: 500;
    background: #fff;
    padding: 13px;
    border: 2px solid #171930;
    cursor: pointer;
    width: 48px;
    height: 48px;
    border-radius: 8px;

    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity 0.3s, visibility 0.3s;
}

.back-to-top__button:hover {
    background-color: #171930;
}

.back-to-top__button:hover path {
    stroke: #fff;
}

.back-to-top__button_state_visible {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
}