Classes from style/buttons.sass. Use the same classes on <button>, <a>, and <NuxtLink>. Stack sizes with full (e.g. btn full color sm).
xxs · xs · sm · md · default · lg · xl · xxl
btn withBorders — transparent background and border; same usage as the “Browse” link in HeaderSection.vue. Combine with size classes (sm, xl, etc.) and with full when you need full width.
Narrow column only for the demo; in chat, the parent sets width.
Cancel / destructive uses the same weight as secondary (light), not red.