提供@Guoliang 的有用评论作为正式答案，因为接受的答案没有回答问题:

Providing @Guoliang's helpful comment as a formal answer, as the accepted answer does not answer the question:

转到 Settings > Editor > Colors &字体 > 常规

Go to Settings > Editor > Colors & Fonts > General

在右侧，展开Text 并选择Default text

根据需要修改背景.