.color-cards-embed {
    border: 3px solid var(--theme-secondary-color);
    border-radius: 30px;
    display: flex; /* flex is fine — no need for inline-flex */
    justify-content: center; /* centers iframe inside */
    background: var(--theme-white-color);
    padding: 10px 20px;
    margin: 0 auto; /* centers the whole box */
    width: fit-content; /* shrink-wrap to content */
}

.color-cards-embed iframe {
    border-radius: 30px;
}