.header__sub-bg{
    display: none;
}
.header__nav:has(.header__menu-item:hover .header__submenu) .header__sub-bg{
    display: block;
    position: absolute;
    background-color: var(--secondary-color-2);
    width: 100%;
    height: 200px;
    z-index: 9999999;
    left: 0;
    margin-top: 20px;
    border-top: 1px solid rgba(0, 0, 0, .1);
}