CSS: Fix parsing of @keyframes rules #11763

Job	Run time
NetBeans on nb-javac	0s
Build Clusters on JDK 17	9m 54s
Build Clusters on JDK 21	8m 10s
Build Clusters on JDK 24-ea	7m 51s
Build-System / Misc Tests on Linux/JDK 17	14m 44s
Check Paperwork on Linux/JDK 17	14m 16s
IDE Modules on Linux/JDK 17	22m 36s
CV on ubuntu-latest/JDK 17	10m 2s
CV on macos-latest/JDK 17	17m 8s
Build ${{ matrix.config }} from src.zip on JDK ${{ matrix.java }}	0s
Build-Tools on Linux/JDK ${{ matrix.java }}	0s
CV on windows-latest/JDK 17	23m 5s
CV on ubuntu-latest/JDK 23	9m 45s
Platform Modules batch1 on Linux/JDK ${{ matrix.java }} (some on 8)	0s
Platform Modules batch2 on Linux/JDK ${{ matrix.java }}	0s
Java Hints ${{ matrix.config }} on Linux/JDK ${{ matrix.java }}	0s
Java Modules on Linux/JDK ${{ matrix.java }}	0s
Java Debugger tests on Linux/JDK ${{ matrix.java }}	0s
JavaFX on Linux/JDK ${{ matrix.java }}	0s
Profiler on Linux/JDK ${{ matrix.java }}	0s
Web Modules on Linux/JDK 17	13m 37s
Groovy on Linux/JDK ${{ matrix.java }}	0s
Rust on Linux/JDK ${{ matrix.java }}	0s
Enterprise on Linux/JDK ${{ matrix.java }}	0s
DB Tests with MySQL on Linux/JDK ${{ matrix.java }}	0s
Versioning Modules on Linux/JDK ${{ matrix.java }}	0s
PHP on ${{ matrix.os }}/JDK ${{ matrix.java }}	0s
GraalVM ${{ matrix.graal }} Tests	0s
LSP tests on Linux/JDK ${{ matrix.java }}	0s
VSCode Extension Tests on JDK ${{ matrix.java }}	0s
Cleanup Workflow Artifacts	2s
	2h 31m 10s

Provide feedback