Hi @영훈 정,
Welcome to Microsoft Q&A forum.
Please also check if Tools > Options… > Text Editor > C#(or the specific language) > Advanced > Editor Color Scheme option is set to Visual Studio 2019.
If you have extensions installed, please confirm that the installed extensions won’t affect the colors of the code(you can disable them temporarily to check).
If the colors were manually changed before, from Tools > Options… > Environment > Fonts and Colors, please check and confirm that they weren’t changed to default.
BTW, the project was developed in VS 2019 and you are using VS 2019 right?
Feel free to let us know the results.
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