Category: Web Development

How px, em and rem actually differ: px is fixed, em compounds from the parent font-size, and rem stays anchored to the root. When to use each.

The RFC 3986 character sets that decide what to percent-encode: unreserved, gen-delims, sub-delims, and how the rules differ per URL component.

Why OKLCH describes colour by lightness, chroma and hue in a perceptually uniform space, and how that makes readable palettes and predictable tints.

HTML entities are text codes that stand in for reserved or awkward characters. What they are, when you must use them, and a reference of the common ones.

How HEX, RGB and HSL describe the same colours in different notations, how to convert between them, and why HSL is easier to reason about by hand.

Each context has its own escaping rules, and mixing them causes bugs and security holes. How JSON, HTML, and URL escaping differ, with worked examples.

What vw, vh, vmin and vmax measure, why 100vh caused mobile scrolling bugs, and how svh, lvh and dvh fix the moving-browser-bar problem.

How UUIDs are structured, why v4 is fully random, how v7 embeds a millisecond timestamp for index locality, and the privacy tradeoff of a time-ordered ID.

How percent-encoding works, reserved vs unreserved characters, encodeURIComponent vs encodeURI, %20 vs +, and the double-encoding bugs that break URLs.

How to read a unified diff: the @@ hunk header, + and – lines, context lines, line-level vs word-level diffs, and when to ignore whitespace.