מחשבון BMI, עיצוב מסך

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:layout_margin="16dp"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:background="#F57F17"
        android:text="My BMI Calculator"
        android:textAlignment="center"
        android:textColor="#004D40"
        android:textSize="34sp"
        android:textStyle="bold" />

    <EditText
        android:id="@+id/etWeight"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:ems="10"
        android:hint="Weight (kg)"
        android:inputType="numberDecimal"
        android:minHeight="48dp"
        android:textAlignment="center" />

    <EditText
        android:id="@+id/etHight"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:ems="10"
        android:hint="Hight (m)"
        android:inputType="numberDecimal"
        android:minHeight="48dp"
        android:textAlignment="center" />

    <Button
        android:id="@+id/btnCalculate"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:onClick="calculateBmi"
        android:text="Calculate"
        android:textSize="20sp"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/tvResult"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:singleLine="false"
        android:text="TextView"
        android:textAlignment="center"
        android:textColor="#311B92"
        android:textSize="20sp" />
</LinearLayout>