.wp-block-details::details-content {
    display: block;
    block-size: 0;
    overflow: hidden;
    transition-property: block-size, content-visibility;
    transition-duration: 0.5s;
    transition-behavior: allow-discrete;
}

.wp-block-details[open]::details-content {
    /*block-size: auto;*/
    block-size: calc-size(auto, size);
}

.width-668 {
    width: 668px;
    margin-left: auto;
    margin-right: auto;
} 
/* Space above the FAQ list. :where() keeps it weaker than a block layout's gap. */
:where(.faq-shortcode) {
    margin-top: 30px;
}