Backport #23174
The CSS styles in Gitea themes are out-of-sync of Chroma's styles.
This PR introduces a `chroma-style-diff.go` tool to compare the diff.
The missing CSS styles have been added manually. They are left as empty
to reduce arguments because there was no color for them before.
And this PR fixes#22348, with just 2 lines changed: `.chroma .kt & .n`,
these colors are taken from GitHub.
It's good enough for #22348
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
- Upgrade stylelint and plugin
- Change ruleset to a explicit one, with all deprecated rules removed
- Fix new issues detected by value validation
For `overflow: overlay` see
https://github.com/stylelint/stylelint/issues/6667
This should eliminate all non-variable color usage in the styles, making
gitea fully themeable via CSS variables. Also, it adds a linter to
enforce variables for colors.
