.opa {
    --time: 300ms;
    --ease: ease-out;

    transition: opacity var(--time) var(--ease), transform var(--time) var(--ease);
    transform: scale(.95);
}

.opa--start {
    opacity: 0;
}

.opa--visible {
    opacity: 1;
    transform: scale(1) rotateX(0);
}