bug(schematics/theme-color): css file generation does not include --mat-sys-surface-container-low

[rschulz-scisys]

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 using the material schematics to generate a color theme, the resulting css file, when not creating scss, does not include the variable --mat-sys-surface-container-low (also missing in the high contrast part)

Reproduction

StackBlitz link:
Steps to reproduce:

1. use the schematics like ng g @angular/material:theme-color
   2.enter any values
2. when asked if to create an scss file, answer no
3. check the resulting css file, the variable as described here https://material.angular.io/guide/system-variables#colors is missing

Expected Behavior

the css file should include a definiton for --mat-sys-surface-container-low also in the high contrast part

Actual Behavior

variable is not present

Environment

• Angular: 19.2.11
• CDK/Material: 19.2.11
• Browser(s): irrelevant
• Operating System (e.g. Windows, macOS, Ubuntu): macos