Guides
How the calculations work, with worked examples.
PX vs REM vs EM vs VW: Which CSS Unit to UseWhen to use each CSS length unit, with real examples.DPI vs PPI: What’s the Difference?Screen pixels, printer dots and why the terms get mixed up.WCAG Color Contrast Requirements ExplainedAA vs AAA, large text, UI components and how to fix failures.Fluid Typography: A Practical GuideType that scales smoothly between phone and desktop.How to Make Images Sharp on Retina ScreensDevice pixel ratio, srcset and the sizes to export.CSS Color Formats: HEX, RGB, HSL and OKLCHWhat each format is for and when to switch.How to Choose a Type ScaleModular scales, ratios and building a usable set of sizes.WebP vs AVIF vs JPEG vs PNGWhich image format to use on the web, and why.How to Choose CSS BreakpointsContent-first breakpoints instead of device lists.How to Prepare Images for PrintResolution, bleed, color mode and file formats for printing.