Six levels of dark mode

A structured breakdown of eight techniques for implementing dark mode on the web, ranging from a simple HTML meta tag to CSS-only approaches and JavaScript integration. Covers the `color-scheme` meta tag, the CSS `color-scheme` property, the `light-dark()` color function, `prefers-color-scheme` media queries, separate stylesheets per scheme, `matchMedia` in JS, building a three-state color scheme switcher, and using `:has()` to query a dynamically injected meta tag instead of adding classes or data attributes.