a {
    transition: all 0.3s ease-in-out;
}

.wp-block-button:not(.is-style-outline) .wp-block-button__link:hover {
    background-color: transparent;
    color: var(--wp--preset--color--theme-primary);
}

.wp-block-button.is-style-outline .wp-block-button__link:hover {
    background-color: var(--wp--preset--color--theme-primary);
    color: var(--wp--preset--color--theme-white);
}