no-unknown-areas

Disallow single-name grid-area references that do not match any named area declared by grid-template-areas in the same stylesheet.

Incorrect

.layout {
  grid-template-areas: "header main";
}

.sidebar {
  grid-area: sidebr;
}

Correct

.layout {
  grid-template-areas: "header main";
}

.header {
  grid-area: header;
}

The rule only checks single-name grid-area declarations. Line-based shorthand placements are ignored.

Related Rules

• no-unused-areas checks the inverse problem: declared template areas without matching item assignments.
• no-overlapping-areas reports duplicate single-name assignments in the same stylesheet.
• Current status explains the same-file assumptions.