bug(material): activated nav-list-item font color is not readable in dark mode

[arkthur]

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

I have an App that uses a sidenav with a nav-list inside. I want the activated nav-list-item to be noticeable, so I'm using that state, but the default behavior with a dark theme, results in an unreadable font color.

Reproduction

StackBlitz link: https://stackblitz.com/edit/components-issue-3qaoos
Steps to reproduce:

1. Open it.
2. See how the first nav list item is activated and barely readable.

Expected Behavior

The background and font color have a minimum contrast, so the item is readable.

Actual Behavior

The background and font color do not have a minimum contrast, so the item is not readable.

Environment

• Angular: 16.1.0
• CDK/Material: 16.1.5
• Browser(s): Chrome 116.0.5845.97 (Official Build) (64-bit)
• Operating System (e.g. Windows, macOS, Ubuntu): Windows 11 (10.0.22621.2134)

[amysorto]

This is something that should be changed in the purple-green prebuilt theme

[arkthur]

This is something that should be changed in the purple-green prebuilt theme

Not only that theme. If, in the StackBlitz, you change the import for @import '~@angular/material/prebuilt-themes/pink-bluegrey.css';, you'll see the other dark prebuilt theme is also not as readable as one would want. Not as terrible as the purple-green one, but not fully accessible, nonetheless.

Contrast ratio (according to Edge's CSS Overview Dev Tools):

• purple-pink: 1.22
• pink-bluegrey: 1.71

If one needs a contrast ratio of 4.5 for AA, and 7 for AAA, none of these prebuilt themes passes the test.