JDK-8292594: Use CSS custom properties for all fonts and colors

[hns]

Please review a patch to complete the conversion of the javadoc style sheet to use CSS custom properties for all colors and fonts.

A few notes for changes that may not be self-explanatory:

• I renamed the --highlight property prefix used for the active navigation/menu/tab item to --selected as the term "highlight" is used for other things such as snippet highlights and active search item targets.
• I unified the active color of copy-to-clipboard buttons to one single value even though they appear on different backgrounds. The value works reasonably well for all uses, and can be changed with a single custom property.
• The stylesheet contains a rule for green line numbers in source pages created with the -linksource option. This is a very rarely used option so I chose to use a custom property with no defined value but a default value. This means the custom property is not contained in the list of custom property definitions in the style sheet, but it can be defined by a theme if needed.
• I removed CSS selectors that are either illegal under HTML 5 such as a[name] or unused.

This change does not affect the appearance of the generated documentation in the browser. I can provide before/after output including different themes if needed.

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8292594: Use CSS custom properties for all fonts and colors

Reviewers

• Jonathan Gibbons (@jonathan-gibbons - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk pull/11109/head:pull/11109
$ git checkout pull/11109

Update a local copy of the PR:
$ git checkout pull/11109
$ git pull https://git.openjdk.org/jdk pull/11109/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 11109

View PR using the GUI difftool:
$ git pr show -t 11109

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/11109.diff

[bridgekeeper]

👋 Welcome back hannesw! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@hns The following label will be automatically applied to this pull request:

• javadoc

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[mlbridge]

Webrevs

• 00: Full (c1a81791)

[jonathan-gibbons]

It's really nice to see those hex constants disappearing from being spread out through the stylesheet.

[openjdk]

@hns This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8292594: Use CSS custom properties for all fonts and colors

Reviewed-by: jjg

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 251 new commits pushed to the master branch:

• 05128c2: 8286185: The Java manpage can be more platform inclusive
• d450314: 8297276: Remove thread text from Subject.current
• cdf9ed0: 8297528: java/io/File/TempDirDoesNotExist.java test failing on windows-x64
• 105d9d7: 8295351: java/lang/Float/Binary16Conversion.java fails with "Unexpected result of converting"
• a80552e: 8236919: Refactor com.sun.tools.javac.main.CommandLine into a reusable module for other JDK tools
• a249a52: 8296754: AutoCreateSharedArchive in JDK 20 is not compatible with JDK 19
• 405b188: 8297570: jdk/jfr/threading/TestDeepVirtualStackTrace.java fails with -XX:-UseTLAB
• ba0a252: 8297717: Remove jdk/internal/misc/TerminatingThreadLocal/TestTerminatingThreadLocal.java from ProblemList
• c05dc80: 8297660: x86: Redundant test+jump in C1 allocateArray
• eff4c03: 8297343: TestStress*.java fail with "got different traces for the same seed"
• ... and 241 more: https://git.openjdk.org/jdk/compare/4a300818fe7a47932c5b762ccd3b948815a31974...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[hns]

/integrate

[openjdk]

Going to push as commit 361b50e.
Since your change was applied there have been 260 commits pushed to the master branch:

• 42b60ed: 8297030: Reduce Default Keep-Alive Timeout Value for httpclient
• 1301fb0: 8296470: Refactor VMError::report STEP macro to improve readability
• 48017b1: 8296804: Document HttpClient configuration properties in java.net.http module-info
• bd51b7e: 8296645: org.openjdk.bench.javax.tools.Javac leaves class files in current directory
• b27a61e: 8297216: Search results omit some methods
• 33dfc7d: 8296954: G1: Enable parallel scanning for heap region remset
• 6f06f44: 8297242: Use-after-free during library unloading on Linux
• 4e8e853: 6788481: CellEditorListener.editingCanceled is never called
• 692bedb: 8297106: Remove the -Xcheck:jni local reference capacity checking
• 05128c2: 8286185: The Java manpage can be more platform inclusive
• ... and 250 more: https://git.openjdk.org/jdk/compare/4a300818fe7a47932c5b762ccd3b948815a31974...master

Your commit was automatically rebased without conflicts.

[openjdk]

@hns Pushed as commit 361b50e.

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