feat(common.scss): improve code markup

[MrLixm]

Hello, here is a quick change to improve rendering of inline code markup (this) for ACES Central.

• more readable background
  • not sure the variable used is the most appropriate but its name make sense for the intended context
• Added padding on left-and right only :
  • no padding on top as without increasing the top margin, 2 block on following lines would superpose and "merge".
• Added small left-right margin :
  • no top/bottom to keep the visual difference minimal, but it would be nice to have, so we can add more top/bottom padding
• added round corners
  • less agressive/sharp look (what's being done by a bit of everybody, github, discord, ...)

I do think the padding/margin changes are quite subjective so let me know if they are not desirable.

side-effect might be some line breaking earlier than before as this markup is now wider (due to margin and padding)

please note that I did not test the changes directly with discourse so I cannot guarantee that they will work once "deployed"

result

change where previewed using a browser extension to customize CSS per page

here is a "before"

[aforsythe]

Thanks @MrLixm

[aforsythe]

Just wondering if you think we should make the large code blocks consistent with the inline code blocks.

See the example below

[MrLixm]

Ha crap I missed it. I think it would actually be better to not touch them. Currently, they are being affected by the new changes because the CSS selector is not explicit enough but I would just make sure the change of this PR doesn't affect them, and don't try to change their style as they might be more complex element that just inline code.

[MrLixm]

New PR #8, let me know what you think.