.default-example .info {
    inline-size: 100%;
    padding: .5em 0;
    font-size: 90%;
    writing-mode: vertical-rl;
}
.scroller {
    text-align: left;
    height: 250px;
    width: 270px;
    overflow-y: scroll;
    display: flex;
    flex-direction: column;
    box-sizing: border-box;
    border: 1px solid black;
    scroll-snap-type: y mandatory;
}

.scroller > div {
    flex: 0 0 250px;
    background-color: rebeccapurple;
    color: #fff;
    font-size: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    scroll-snap-align: end;
}

.scroller > div:nth-child(even) {
    background-color: #fff;
    color: rebeccapurple;
}