Szétváló felület

.we-btn-split {
    position: relative;

    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 16px;

    min-width: 170px;
    height: 54px;

    padding: 0 26px;

    border: 1px solid rgba(255,255,255,.14);
    border-radius: 14px;

    background: transparent;
    color: #f2f4f0;

    font-family: Arial, sans-serif;
    font-size: 14px;
    font-weight: 500;

    cursor: pointer;

    overflow: hidden;

    transition:
        transform .4s cubic-bezier(.22,1,.36,1),
        border-radius .5s ease,
        box-shadow .5s ease;
}

.we-btn-split-left,
.we-btn-split-right {
    position: absolute;

    top: 0;

    width: 51%;
    height: 100%;

    background: #151e22;

    transition:
        transform .65s cubic-bezier(.22,1,.36,1);
}

.we-btn-split-left {
    left: 0;
}

.we-btn-split-right {
    right: 0;
}

.we-btn-split-text,
.we-btn-split-arrow {
    position: relative;
    z-index: 3;

    transition:
        transform .55s cubic-bezier(.22,1,.36,1),
        color .35s ease;
}

.we-btn-split-arrow {
    font-size: 19px;
}

.we-btn-split:hover {
    transform:
        translateY(-3px);

    border-radius: 18px;

    box-shadow:
        0 18px 38px rgba(0,0,0,.4);
}

.we-btn-split:hover .we-btn-split-left {
    transform:
        translateX(-88%);
}

.we-btn-split:hover .we-btn-split-right {
    transform:
        translateX(88%);
}

.we-btn-split:hover .we-btn-split-text {
    transform:
        translateX(-4px);
}

.we-btn-split:hover .we-btn-split-arrow {
    transform:
        translateX(7px)
        scale(1.1);
}

.we-btn-split:active {
    transform:
        translateY(0)
        scale(.97);
}

Ehhez az animációhoz nincs külön JavaScript.