Cannot resolve symbol '@style/Theme.AppCompat'

since android studio upgrade to Android Studio Dolphin | 2021.3.1, the layout xml shows "Cannot resolve symbol '@style/Theme.AppCompat' " Here is a screenshot of the code

the build.gradle is:

dependencies {
implementation 'androidx.appcompat:appcompat:1.4.0'
...
}

When I comment out this line of code, everything becomes normal:

dependencies {
//    implementation 'androidx.appcompat:appcompat:1.4.0'
...
}

When I press the key combination ctrl+left mouse button on "android:theme="@style/Theme.AppCompat" to quickly guide to the following position, as shown in the figure: Theme.AppCompat is here in the values.xml

I don't know what this is, who can tell me?