body {
    margin: 0;
    overflow: hidden;
    background-color: white; /* était "black" */
}

.portail-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;

    display: flex;
    justify-content: center;
    align-items: center;

    overflow: hidden;
}

.porte {
    height: 100%;
    width: 50%;
    margin: 0;
    border: none;
    flex-shrink: 0;
    object-fit: contain;
    object-position: center;
    transition: transform 3s ease-in-out;
}

.porte-gauche {
    margin-right: -5px;
}

.portail-container.ouvert .porte-gauche {
    transform: translateX(calc(-100% + 5px));
}

.portail-container.ouvert .porte-droite {
    transform: translateX(100%);
}