3.4 Success Criterion 1.4.11 – Non-Text Contrast

All non-text content (e.g. graphics, diagrams, buttons, checkboxes, radio buttons or input fields), which deliver important information, should have a minimum 3:1 colour contrast ratio against adjacent colour.

Before Rectification

The grey textboxes on the white background have poor colour contrast, making it harder for persons with low vision to identify.

After Rectification

Dark border is applied to the textboxes so that they can be identified easily.

WCAG 2 Reference:
https://www.w3.org/WAI/WCAG21/Understanding/non-text-contrast.html