/* mainstages fade-in */
@keyframes anim-fade-in {
    0% {
        opacity: 0
    }

    to {
        opacity: 1
    }
}

section [class*="mn_"] {
    animation: anim-fade-in 0.5s ease-out both;
    animation-timeline: view();
    animation-range: entry 25% entry 60%;

    /* Animation properties create a new stacking context; this z-index
       keeps descendants from falling behind siblings with z-index: 0. */
    position: relative;
    z-index: 1;
}