Challenge 1: Changing the Master's Title Colour — Solution Walkthrough

Steps:
  1. View > Slide Master.
  2. Click the very top thumbnail (the Master slide itself, not one
     of the indented Layouts beneath it).
  3. Select the title placeholder text and change its font colour.
  4. Close Slide Master view and return to Normal view.

Which slides update:

Every slide in the presentation whose title hasn't been manually
overridden updates to the new colour — regardless of which specific
Layout (Title Slide, Title and Content, etc.) each individual slide
is using.

Why editing the Master affects all of them:

The Slide Master sits at the TOP of PowerPoint's design hierarchy —
every Layout inherits its base formatting from the Master, and every
slide inherits from whichever Layout it uses. Changing the Master's
title colour changes the shared definition that every Layout (and
therefore every slide built from any of them) reads its own title
colour from, unless that specific property has been individually
overridden somewhere further down the chain. This is exactly the
"edit once, everything downstream updates" behaviour this chapter
compares directly to modifying a Word Style — the Master is simply
the top of a two-level inheritance chain (Master to Layout to slide)
rather than the single flat list Word's styles use.