コードブロックのサイジングと配色を改善

[jordan.vidrine]

@fitzy

However, we lost the change to the max-height in commit 98b2763. Was this intentional? I see it was commented out and then deleted in a subsequent commit.

If so, I can still live with a local override.

Yes it was deleted as to remain as close to our current codeblock size as possible.