コードブロックのサイジングと配色を改善

[jordan.vidrine]

@david

It looks like the new padding is only applied to .hljs elements, which means that simple code blocks (with no highlighting) don’t get it:

@NateDhaliwal

Could the darker background also be applied, for consistency?

Thanks for noticing these! I have updated those styles to apply to code rather than just hljs blocks.