File drop — accessibility

Keyboard

• Tab focuses the surface; Enter or Space opens the file dialog.
• While uploading or disabled the surface leaves the tab order (tabIndex=-1).

ARIA

• role="button" on the surface, its name is the label text.
• aria-describedby → the formats line, plus the error line when there is one.
• aria-busy="true" while uploading; the Progress inside has role="progressbar" with its own aria-label.
• aria-disabled="true" when inert.
• The error line is aria-live="polite" and is always in the DOM (empty when there is no error) so the announcement fires.

Focus

2 px --accent outline, 2 px offset, on :focus-visible.

Contrast

Label --fg on --surface-75; formats --fg-muted is supplementary text (owner 3 Oct 2026); error --critical-ink meets AA.

Known limits

• Only the first file is taken.
• The type check trusts an empty MIME type (browsers leave it empty for .ico) — the server decides by content.
• Drag-over is not announced to screen readers; it is a mouse-only affordance.