Apply contrast and spacing for legibility — calibrating color contrast between text and background, character tracking, and line leading so a chosen typeface and size actually render legibly. Use when picking text colors, choosing background colors that will carry text, evaluating accessibility against WCAG, fine-tuning typography for production rendering, or auditing why text "looks designed" but is hard to read. Even a perfect typeface at the right size will fail if contrast is too low, tracking too tight, or leading too cramped.
