css-viewport-size

CSS custom properties combined with viewport units and trigonometric functions let you calculate and expose viewport dimensions directly in stylesheets. Define custom properties that dynamically reference viewport width and height, then apply them to responsive styles without JavaScript dependencies.

Yes. CSS custom properties enable responsive measurements by calculating viewport-dependent values at render time. This approach replaces JavaScript-based viewport detection for layout decisions, letting CSS manage size-aware styling natively.

CSS custom properties (variables) store reusable values that can reference viewport units like vw and vh. Combined with calc(), they compute dynamic measurements tied to screen dimensions, updating automatically when the viewport changes.

Use CSS-only approaches when you need simple responsive adjustments without runtime JavaScript overhead. This works well for layout scaling, font sizing, and spacing tied to viewport size, keeping stylesheets self-contained and performant.

Yes. CSS calc() function performs arithmetic with custom properties and viewport units, enabling complex measurements. Trigonometric functions in modern CSS also support advanced calculations for viewport-relative sizing.