What: Ensuring sufficient contrast between text and background so everyone can read it.
Why: Reading is a right; low-contrast text excludes many readers.
How: Make normal-text contrast at least 4.5:1 (AA), and check every text/background pair, not just the body.
Common mistake: An 'elegant' light grey on white that fails in bright light.
Exercise: Check a design's contrast and fix every text below the threshold.