CSS Outline

CSS Outline — CSS outline adds visible focus indicators. Essential for keyboard accessibility and focus management. The guide walks through Outline Properties. `outline: 2px solid blue` — shorthand (width, style, color). `outline-offset: 2px` — space between element border and outline. Unlike border, outline does NOT affect element size or layout. `:focus-visible { outline: 2px solid Highlight }` — keyboard-only focus ring. Use outline for: focus indicators without layout shift, debugging element boundaries. The guide is organized into 1 sections that build on each other, each pairing a prose explanation with real CSS you can use as-is. Related guides: CSS Introduction, CSS Selectors, CSS Box Model, CSS Flexbox, CSS Grid. This is one of 68 CSS guides on CSS Reference — see the full list on the guides page. Look up any property mentioned in this guide from the search page or the CSS Reference homepage.