@moniuch

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

When some styles in my project's mat-select (20.1.5) broke, I found out that all the --mat-option-* CSS variables were undefined (or at least this is what Chrome 139 DevTools claims).

This brought me to mat-select examples page for comparison. Seems like these vars aren't defined there either (20.2.0) - all looks unbroken because the fallbacks kick in. (I don't have them in my project for some reason.) This used to work before.

Could you please verify that this is the expected state of --mat-option-* CSS variables?
Could you confirm that they are defined only as tokens, but are not expected to contain any values in your builds?

Reproduction

(The problem is not really reproducible, but leads to a discovery that is difficult to interpret - whether it is package fault or consumer's fault)

Expected Behavior

mat-option hover should have a non-transparent background

Actual Behavior

mat-option hover has a transparent background

Environment

• Angular: 20.1.6
• CDK/Material: 20.1.5
• Browser(s): Chrome 139
• Operating System (e.g. Windows, macOS, Ubuntu): macOS