bug(Datepicker): transparent dropdown and shifting all content down when open

[troncomputers]

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

I started this project with ver. 20.1.0 and upgraded to 20.1.3 - nothing changed

Description

All dropdowns, all dialogs are transparent and datepicker shifts all content when opened

Reproduction

StackBlitz link: https://stackblitz.com/edit/angular-qzxnk5dr

Expected Behavior

All dropdowns should have background-color from theme

Actual Behavior

All dropdowns, all dialogs are transparent and datepicker shifts all content when opened

Environment

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/ \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|

/ △ \ | '_ \ / | | | | |/ _ | '__| | | | | | |
/ ___ | | | | (| | || | | (| | | | || | | |
// __| ||_, |_,||_,|| _|||
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Angular CLI: 20.1.2
Node: 22.17.0
Package Manager: npm 11.1.0
OS: win32 x64

Angular: 20.1.2
... animations, build, cli, common, compiler, compiler-cli, core
... forms, platform-browser, platform-browser-dynamic, router

Package Version

@angular-devkit/architect 0.2001.2
@angular-devkit/core 20.1.2
@angular-devkit/schematics 20.1.2
@angular/cdk 20.1.3
@angular/material 20.1.3
@schematics/angular 20.1.2
rxjs 7.8.2
typescript 5.8.3
zone.js 0.15.1

[crisbeto]

You're likely missing a theme.