Gradle build "Error:resource android:style/TextAppearance.Material.Widget.Button.Borderless.Colored not found."

Question

I'm trying to build an Android project with the following app build.gradle:

android {
    compileSdkVersion 26

    defaultConfig {
        applicationId "com.myapp"
        minSdkVersion 26
        targetSdkVersion 26
        versionCode 1
        versionName "1.0.0"
        ndk {
            abiFilters "armeabi-v7a", "x86"
        }
    }
    ....
}

When I run a gradle sync, I get the following errors:

Error:resource android:style/TextAppearance.Material.Widget.Button.Borderless.Colored not found.
Error:resource android:style/TextAppearance.Material.Widget.Button.Colored not found.

I read here that these resources weren't added until API 24, but I was under the impression that I'm building for version 26 (since that's what's listed in build.grade).

Clicking on these doesn't take me to the location, but I think that these come from a 3rd party library that I'm using. Not positive about that, but I'm still investigating and will update if I make progress. In the meantime, am I missing something obvious here?