Step 7: Solution

Here's the code from step 7

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/colorBgDark"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    
    <de.hdodenhof.circleimageview.CircleImageView
        android:id="@+id/iv_circle"
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:layout_marginBottom="72dp"
        android:src="@color/colorSun"
        app:layout_constraintBottom_toTopOf="@+id/second_bg"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <android.support.v7.widget.CardView
        android:id="@+id/cardview"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginStart="16dp"
        android:layout_marginEnd="16dp"
        android:layout_marginBottom="16dp"
        app:cardBackgroundColor="@color/cardview_light_background"
        app:cardCornerRadius="8dp"
        app:cardElevation="2dp"
        app:contentPadding="16dp"
        app:layout_constraintBottom_toBottomOf="@+id/second_bg"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="@+id/guideline_horizontal20" />

    <View
        android:id="@+id/second_bg"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:background="@color/colorBg"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="@+id/guideline_horizontal30" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline_verticalHalf"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.5"/>

    <android.support.constraint.Guideline
        android:id="@+id/guideline_horizontalHalf"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.5"/>

    <android.support.constraint.Guideline
        android:id="@+id/guideline_horizontal20"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.20" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline_horizontal30"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.30" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline_horizontal38"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.38" />

</android.support.constraint.ConstraintLayout>