.megamenu-background-shade {
    --duration: .1s;

    position: fixed;
    width: 100vw;
    height: 100vh;
    top: 0;
    left: 0;
    background-color: transparent;


    transition-property: background-color;
    transition-duration: var(--duration);
    transition-timing-function: linear;

    pointer-events: none;
    z-index: 1;
}

body:has(li.menu-item .megamenu.none) .megamenu-background-shade {
    background-color: rgba(0, 0, 0, .65);
}

header {
    z-index: 2;
    position: relative;
}