3.21.2. Activating High Contrast 
This feature can help users with vision impairment and people with little or color perception issues to be able to read text easier.
Step by Step
- Click your user name and navigate to Settings > General > Accessibility.
- Check the Enable high contrast mode for the header bar box.
The header part in the top of your web browser, should be significantly darker compared
to the grey color used by default:
‣ Parent topic: Section 3.21. Accessibility Features