Premium buttons with a diagonal sheen that sweeps across on hover: a gradient button with a top highlight and inner glow, a frosted glass button and a dark metal button. A soft idle sheen is built in. Pure CSS. Button component props: label, url, look (gradient|glass|metal), size (s|m|l), badge (small pill shown only when filled). Options (data attributes on the section): data-theme (light|dark) surface; data-align (start|center|end) row alignment; data-speed (fast|normal|slow) sweep speed; data-anim (rise|fade|none) entrance. Real links, focus rings, reduced-motion shows a static highlight.