Oh! I like how Amazon's signup page changes with this technique
The contrast ratios displayed here are not compliant. Users with subpar monitors, poor eyesight, colour blindness are likely not going to even see the fields.
I see you have (quite rudely) responded to a similar comment on your article, and your response was:
The image example is for demonstrating the concept and principle. It’s not dictating that you should use the exact colors you see on it, so there’s no use in nitpicking at that. If you want to make it 3:1, darken the borders.
I think this negates your article a little "If you want to make it 3:1, darken the borders" - it also displays a bit of a lack of conviction in your suggestion. If you want to demonstrate a solid design principle, it should work in the example.
Off-white text fields draw attention to each field quickly so users can interact with them right away. They also provide a clearer focus on the input so users can type, check, and correct them easier.
Any evidence to support this? Would be very nice to see some if you do have it.
You've noted that Amazons form is: 1. Harder to focus on input 2. Discourages interaction 3. Unappealing impression
My impression is that it's very likely that Amazon have put a great deal of focus into the usability and performance of their forms
It’s important to note that off-white does not equal gray. Avoid using solid gray text fields because users tend to perceive them as disabled or inactive. They can also make input and placeholder text harder to read.
I think this would cause issues for colour blind folks