Multi-select photo cards for quizzes and onboarding. Each card is a label around a real checkbox (works without JavaScript), with a photo and a white label strip in the bottom-right corner that has inverted (concave) corners drawn with box-shadow pseudo-elements. A section heading and helper line sit above the grid. Checked cards darken the label and fill the tick box. Card component props: image, imageAlt, label. Below 30em of card width the notch becomes a full-width label. Options (data attributes on the section): data-theme (light|dark) surface behind the cards; data-anim (rise|fade|none) entrance; data-cols (2|3) cards per row on wide screens.