tachiyomi/app/src/main/res/layout/reader_reading_mode_settings.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:clipToPadding="false"
    android:padding="16dp">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <!-- Series-specific preferences -->

        <TextView
            android:id="@+id/viewer_text"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="@string/pref_category_for_this_series"
            app:layout_constraintBaseline_toBaselineOf="@id/viewer"
            app:layout_constraintEnd_toStartOf="@id/verticalcenter"
            app:layout_constraintStart_toStartOf="parent" />

        <androidx.appcompat.widget.AppCompatSpinner
            android:id="@+id/viewer"
            android:layout_width="0dp"
            android:layout_height="24dp"
            android:entries="@array/viewers_selector"
            app:layout_constraintEnd_toEndOf="@id/spinner_end"
            app:layout_constraintStart_toEndOf="@id/verticalcenter"
            app:layout_constraintTop_toTopOf="parent" />

        <!-- Pager preferences -->

        <include
            android:id="@+id/pager_prefs_group"
            layout="@layout/reader_pager_settings"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:visibility="gone"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/viewer"
            tools:visibility="visible" />

        <!-- Webtoon preferences -->

        <include
            android:id="@+id/webtoon_prefs_group"
            layout="@layout/reader_webtoon_settings"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:visibility="gone"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@id/viewer" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/verticalcenter"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            app:layout_constraintGuide_percent="0.5" />

        <android.widget.Space
            android:id="@+id/spinner_end"
            android:layout_width="16dp"
            android:layout_height="0dp"
            app:layout_constraintStart_toEndOf="parent"
            tools:ignore="MissingConstraints" />

    </androidx.constraintlayout.widget.ConstraintLayout>

</androidx.core.widget.NestedScrollView>