Misc: Font weight variables

[Sereza7]

Jira URL

None, misc change proposed and validated in https://forum.xwiki.org/t/css-best-practice-dont-hard-code-font-weights/14490 .

Changes

Description

• Added three LESS variables in the global context to avoid hardcoding font weights.

Clarifications

• Those are the most used values in the code base, 400 is the same as normal and 700 is the same as bold. From what I could see, we don't need a light font weight because it's not really used anywhere in XWiki nowadays and it'd probably be a liability for the text lisibility.

Screenshots & Video

None.

Executed Tests

None, this change has no influence on the compiled LESS and respects code style.

Expected merging strategy

• Prefers squash: Yes
• Backport on branches:
  • 16.10.X (safe change)

[michitux]

Why are you adding new LESS variables? Unless there are problems with browser support or customization support, this should be added as CSS variables imho. Also, introducing something similar to a new API doesn't seem like a misc change to me.

[michitux]

Why are you adding new LESS variables? Unless there are problems with browser support or customization support, this should be added as CSS variables imho.

While it might not seem consistent, to me the problem of adding new LESS variables is that it means that these new variables cannot be used in CSS code so for using these variables we would need to convert even more code to LESS which is absolutely against what we should be doing (converting from LESS to plain CSS). On the other hand, I think it shouldn't be any problem to use CSS variables in LESS code.