SYSTEM

Separator

A 1px rule: ink when it opens or closes something, a hairline for repetition.

Content shadcn: Separator

Ink: opens or closes


Hairline: repeats


Left Right

Anatomy

Weight 1px, always
Ink structure that opens or closes something: section heads, the top and head of a table, a field’s rule, a layer’s frame, the rule under tabs
Hairline --border, for repetition: table rows, index rows, captions, menu items
Vertical a hairline between two things side by side
Hover a rule already on the page is where hover develops (Motion, 11); a separator never changes colour on its own

Decisions

  • Frames off

    A straight line organises the page; it never boxes one item. Rules stay, boxes go, and the only four-sided frame is a layer over the page.

  • Two weights

    Ink opens or closes, a hairline repeats: the weight says which.

  • No radius, no shadow

    border-radius is 0 everywhere and there are no box-shadows.