CSS: Fix parsing of @keyframes rules #11736

Job	Run time
Build Clusters on JDK 17	9m 56s
Build Clusters on JDK 21	8m 27s
NetBeans on nb-javac	0s
Build Clusters on JDK 24-ea	7m 32s
CV on ubuntu-latest/JDK 17	8m 32s
CV on macos-latest/JDK 17	21m 54s
Check Paperwork on Linux/JDK 17	14m 14s
Build-System / Misc Tests on Linux/JDK 17	13m 51s
CV on windows-latest/JDK 17	14m 58s
IDE Modules on Linux/JDK 17	19m 24s
CV on ubuntu-latest/JDK 23	9m 48s
Build ${{ matrix.config }} from src.zip on JDK ${{ matrix.java }}	0s
Platform Modules batch2 on Linux/JDK ${{ matrix.java }}	0s
Build-Tools on Linux/JDK ${{ matrix.java }}	0s
Platform Modules batch1 on Linux/JDK ${{ matrix.java }} (some on 8)	0s
Java Debugger tests on Linux/JDK ${{ matrix.java }}	0s
Java Hints ${{ matrix.config }} on Linux/JDK ${{ matrix.java }}	0s
Java Modules on Linux/JDK ${{ matrix.java }}	0s
Profiler on Linux/JDK ${{ matrix.java }}	0s
Groovy on Linux/JDK ${{ matrix.java }}	0s
JavaFX on Linux/JDK ${{ matrix.java }}	0s
Web Modules on Linux/JDK 17	13m 50s
Enterprise on Linux/JDK ${{ matrix.java }}	0s
Rust on Linux/JDK ${{ matrix.java }}	0s
DB Tests with MySQL on Linux/JDK ${{ matrix.java }}	0s
PHP on ${{ matrix.os }}/JDK ${{ matrix.java }}	0s
Versioning Modules on Linux/JDK ${{ matrix.java }}	0s
GraalVM ${{ matrix.graal }} Tests	0s
VSCode Extension Tests on JDK ${{ matrix.java }}	0s
LSP tests on Linux/JDK ${{ matrix.java }}	0s
Cleanup Workflow Artifacts	2s
	2h 22m 28s

Provide feedback