[Code block] Evaluate the background color

[thyhmdo]

Problem

Currently, our website is on the Gray 10 background, so it should have a white layering token. The code blocks are in darker gray (examples below). This was probably because we had pulled the code block and code snippets inconsistently from Gatsby and Carbon.

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Action

Evaluate if we need to update this or if it should be fine because it depends on the different use cases. If it's pulled from Carbon, it also has the copy feature which might not be necessary when we document keyboard interactions.

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Here are a few other examples

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An example that could correct the issue if we want these code blocks to follow the layering logic: