Color Alone, Color Contrast, Color Conflicts

Not color alone

Text
Underline
Patterns, shapes. icons
Position
Brightness (3:1 contrast ratio) with hover/focus
Other text styling
- Bold
- Italics
- Size

Examples

Text for error messages

Last Name - please provide a last name

Underline for link in a sentence

The link is underlined!

Bold for link in a sentence

The link is emboldened! However, if you plan to emphasize content on your site, then you're back to having an issue.

Shapes used in a bar chart

Legend

Lions
Tigers
Bears