.splitflap {
    position: relative;
    min-width: 25px;
    height: 25px;
    margin: 1px;
    line-height: 25px;
    font-size: 25px;
    font-family: Monospace, serif;
    text-align: center;
    color: black;
}

.sfcenter {
    min-width: 297px;
    left: 0;
    width: 100%;
    display: flex;
    justify-content: center;
}

.sftop {
    position: relative;
    height: 50%;
    width: 100%;
    background-color: white;
    border-radius: 5px 5px 0 0;
    overflow: hidden;
    z-index: 0;
}

.sfbottom {
    position: relative;
    height: 100%;
    width: 100%;
    margin-top: -50%;
    border-radius: 5px;
    z-index: -1;
    background-color: white;
    transform-origin: center;
}

.nextHalf {
    position: relative;
    height: 50%;
    width: 100%;
    margin-top: -100%;
    overflow: hidden;
    border-radius: 5px 5px 0 0;
    z-index: 2;
    background-color: white;
    transform-origin: bottom;
}

.nextFull {
    position: relative;
    height: 100%;
    width: 100%;
    background-color: white;
    margin-top: -50%;
    border-radius: 5px;
    z-index: -3;
}

.flip1 {
    animation: flip1 ease-in 1;
    animation-duration: 1s;
}

.flip2 {
    animation: flip2 ease-out 1;
    animation-duration: 1s;
}

@keyframes flip1 {
    0% {
        transform: rotateX(0deg);
        background-color: white;
    }
    50% {
        transform: rotateX(90deg);
        background-color: white;
    }
    100% {
        transform: rotateX(90deg);
    }
}

@keyframes flip2 {
    0% {
        transform: rotateX(-90deg);
    }
    50% {
        transform: rotateX(-90deg);
    }
    100% {
        transform: rotateX(0deg);
        background-color: white;
    }
}