width

   override fun onStart() {
        super.onStart()
        dialog?.window?.setLayout(
            ViewGroup.LayoutParams.MATCH_PARENT,
            ViewGroup.LayoutParams.WRAP_CONTENT
        )
    }

Margin

val back = ColorDrawable(Color.TRANSPARENT)
val inset = InsetDrawable(back, 40)
dialog!!.window!!.setBackgroundDrawable(inset)

or

android:background="@drawable/dialog_background"

margin by xml

`dialog_background`

<?xml version="1.0" encoding="utf-8"?>
<inset xmlns:android="http://schemas.android.com/apk/res/android"
    android:drawable="@drawable/dialog_background_gradient"
    android:insetLeft="40dp"
    android:insetRight="40dp" />

`dialog_background_gradient`

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <gradient
        android:angle="90"
        android:centerColor="#FFFFFF"
        android:endColor="#000000"
        android:startColor="#FFFFFF"
        android:type="linear"
        android:useLevel="true" />
    <corners android:radius="5dp" />
</shape>

Html

https://developer.android.com/guide/topics/resources/string-resource#StylingWithHTML

not work:

getHtmlString(
 getString(R.string.dialog_sub_title, 
  getAmount(coin), 
  getTask(task)))

<string name="dialog_sub_title">
  Download the app1 <font color="#FF6237">%1$s</font>,\n 
  Download the app2 <font color="#FF6237">%2$s</font> 
</string>

work well:

add CDATA: https://developer.android.com/reference/org/w3c/dom/CDATASection

add <b></b>: blod

getHtmlString(
 getString(R.string.dialog_sub_title, 
  getAmount(coin), 
  getTask(task)))

<string name="dialog_sub_title">
 <![CDATA[ 
   Download the app1 <font color="#FF6237"><b>%1$s</b></font>,\n 
   Download the app2 <font color="#FF6237">%2$s</font> 
 ]]>
</string>