demo · v137

System Accent

The new AccentColor system keyword lets accent-color follow whatever the OS / browser theme is set to. Form controls match the rest of the UI without per-OS detection. Change your OS accent and refresh — the left column updates, the right one stays generic.

probing…
your system AccentColor

Without (default)

accent-color: AccentColor

the code

input, progress {
  accent-color: AccentColor;       /* OS accent */
  /* color: AccentColorText;         pairs with this for text on the accent */
}

see also