Amount input

Keyboard

• Typing digits, , and . works as described in Usage; letters and other characters are ignored.
• Arrow ↑ / ↓ increment / decrement by one (replacement for the native number stepper).
• The caret stays after the same digit while grouping spaces appear or disappear, including right after the decimal comma (12, + 5 → 12,5).
• Tab / Shift+Tab move focus normally; on blur an undecided dot (12.5) becomes 12,5.

ARIA

• Native <input type="text"> with inputMode="decimal" / "numeric" — mobile keyboards show digits.
• Accessible name from the wrapping DS Field label or ariaLabel.
• aria-describedby links the hint / error under a DS Field automatically (useFieldDescribedBy); a host can pass describedBy explicitly.
• aria-invalid="true" when the host marks the value invalid, and for a count (decimals={0}) left with an undecided dot (12.3) on blur — that value is not saved.
• The unit suffix is aria-hidden; the unit must be part of the label.

Focus

• Standard DS input focus ring on the shell (.acrm-inputwrap:focus-within).
• No focus traps; the field never moves focus on its own.

Contrast

• Text uses --fg on --surface-100 (AA).
• Suffix uses the muted tone of .acrm-amount-suffix; it repeats information already in the label, so it is not the only carrier of meaning.
• Error state uses the DS field error ink (--critical-ink) plus aria-invalid.

Known limits

• The dot rule applies to locales with a decimal comma (cs). In a decimal-dot locale (en) the comma is a grouping separator and the dot is always decimal.
• A refused keystroke gives no audible feedback — the value simply does not change.