UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.112 Safari/537.36

Steps to reproduce the problem:
1. Open the attached testcase in Chrome.
2. Observe the background colors of the words "Green".

What is the expected behavior?
Their background colors should be green.
See attached Safari screenshot (which is correct except for the <input type="color"> because Safari doesn't yet support <input type="color"> and thus interprets it as <input type="text">).

What went wrong?
Their background colors are red, indicating that the <input>s in question did not match the :read-only CSS pseudo-class, even though they should according to the current spec.
See attached Chrome screenshot.

Did this work before? No 

Chrome version: 52.0.2709.0  Channel: canary
OS Version: OS X 10.11.4
Flash Version: Shockwave Flash 21.0 r0

The spec admittedly gives unintuitive results here. I'm just arguing about spec compliance, not about the (un)reasonableness of the spec.

https://html.spec.whatwg.org/multipage/scripting.html#selector-read-only
> The :read-only pseudo-class must match all other HTML elements [which don't match :read-write].

https://html.spec.whatwg.org/multipage/scripting.html#selector-read-write
> The :read-write pseudo-class must match any element falling into one of the following categories [...]:
> * <input> elements to which the `readonly` attribute applies, and that are mutable (i.e. that do not have the `readonly` attribute specified and that are not disabled)
> * <textarea> elements that [...]
> * elements that are editing hosts or editable and are neither input elements nor textarea elements

Per the table in https://html.spec.whatwg.org/multipage/forms.html#concept-input-apply ,
the `readonly` attribute does not apply to <input>s of type hidden, range, color, checkbox, radio, file, image, submit, reset, or button.
Thus, such <input>s don't match :read-write, and therefore must match :read-only.

Note that MS Edge currently suffers from the same bug, and Firefox doesn't currently implement :read-only or :read-write.
 

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