body {
    overflow: visible;
}
.flipbook-viewport {
overflow: visible !important;
width: 100%;
height: auto !important;
}
.page-wrapper {
    overflow: visible !important;
}
.btn {
    height: 30px;
    background-color: transparent !important;
    border:none;
    font-size: 36px;
}

.btn-zoom {
    height: 20px;
    background-color: rgb(255, 247, 13) !important;
    border:none;
    padding: 10px;
    border-radius: 30px;
    color: white;
}

@media screen and (max-width: 400px) {
    .flipbook-viewport {
        max-width: 320px;
    }

    .btn {
        height: 230px;
        background-color: transparent !important;
        border:none;
        font-size: 36px;
    }
}