Add Angular Material Color theme

[twerske]

Add an Angular Material color theme for formatting code for decks following the styling of Angular Material.

This custom theme is currently used for all external slides by the Angular team at Google - so having a drop down option would be super helpful!

[romannurik]

Hi there! Two things:

1. This doesn't actually allow you to choose the color theme from the dropdown (you need to edit index.html for that)
2. What is this theme? Is this for decks for the Angular Material team? Some description might be useful :)

[twerske]

@romannurik sorry for the massive massive delay on this - I've updated the PR with the dropdown html and added a description. As on 2021+ this theme is the official external code styling theme of Angular's code snippets in slides, so it'd be great to be a dropdown!

[romannurik]

Hi there! Almost ready to merge! Just one piece of feedback:

• The contrast between regular text (F8F9FA) and comments (grey 300) is somewhat low ... can comments be a bit darker?
• The contrast between the dimmed color (grey 400) and comments (grey 300) is also somewhat low ... you may want to make dimme text very dimmed as it's normally part of a slide progression / legiiblity less important

But -- I leave this entirely up to you... happy to merge as-is if you prefer.

[twerske]

Updated and addressed those colors - we're prioritizing visual simplicity over accessibility of unfocused content

[romannurik]

Looks great!