Datepicker comparison ranges uses substandard colors

### Describe the problem that you experienced

Up until V17 (excl.) the Datepicker Docs showed clear distinctions between the primary and accent colors, which made the example at the "Date range picker comparison ranges" section valuable. However, starting with the V17 docs (up until and including the current version), Angular Material started using Material 3 and some of the default themes (especially Azure & Blue) now don't show much of a color distinction (if at all), making the example barely useful with that respective color scheme.

Maybe it gets better with Material 3 Expressive, but I don't have particularly high hopes. Also, older versions will always have a docs page, still.

### Enter the URL of the topic with the problem

https://material.angular.dev/components/datepicker/overview

### Describe what you were looking for in the documentation

_No response_

### Describe the actions that led you to experience the problem

_No response_

### Describe what you want to experience that would fix the problem

More distinction between primary and accent colors, or actually custom defined colors for this example.

### Add a screenshot if that helps illustrate the problem

### If this problem caused an exception or error, please paste it here

```true

```

### If the problem is browser-specific, please specify the device, OS, browser, and version

```true

```

### Provide any additional information here in as much as detail as you can

```true

```

material.angular.dev/components/datepicker/overview の datepicker 概要にある「Date range picker comparison ranges」セクションを開き、現在の Material 3 themes、特に Azure と Blue で primary color と accent color を比較します。例のドキュメントと theme styling のエントリポイントを追跡し、その後、ドキュメント化されている themes で 2 つの範囲が視覚的に区別できること、また旧バージョンのドキュメントに影響がないことを確認します。

索引モデルが issue の本文から書いたものです。