.st-viewer {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    z-index: 250;
    background-color: white;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}


    .st-viewer.show {
        opacity: 1;
        visibility: visible;
    }


.img-animation {
    display: block;
    margin: 0 auto;
    height:250px;
    width:auto;
}

.img-enter {
    animation: imgslideInFromLeft 2s ease forwards;
}

.img-exit {
    animation: imgslideOutToRight 2s ease forwards;
}

@keyframes imgslideInFromLeft {
    0% {
        transform: translateX(-100vw); /* fora da tela totalmente à esquerda */
        opacity: 0;
    }

    100% {
        transform: translateX(0); /* posição original */
        opacity: 1;
    }
}

@keyframes imgslideOutToRight {
    0% {
        transform: translateX(0); /* posição original */
        opacity: 1;
    }

    100% {
        transform: translateX(100vw); /* sai totalmente para a direita */
        opacity: 0;
    }
}