Fixed Header Test
Fixture 01 — Verifies side-panel coexistence with a position: fixed header at the top of the page.
🧪 Manual Test Checklist
- Side panel opens and closes
- Fixed header stays at top (not pushed right)
- Fixed header doesn't overlap the panel content
- Scrolling works independently in page and panel
Understanding Container Queries
Container queries allow elements to respond to the size of their parent container rather than the viewport. This fundamentally changes how we build responsive components. Instead of relying on viewport breakpoints, each component can adapt based on its own available space. This is especially powerful in design systems where the same card component might appear in a narrow sidebar, a medium main column, or a full-width hero layout.
The Rise of View Transitions
The View Transitions API enables smooth animated transitions between different states of a page, or even between pages in multi-page applications. By leveraging the browser's built-in animation capabilities, developers can create polished, app-like navigation experiences without heavy JavaScript animation libraries. The API captures snapshots of old and new states and animates between them automatically.
Mastering CSS Anchor Positioning
CSS Anchor Positioning is a powerful new feature that lets you tether elements to each other declaratively. Tooltips, popovers, and dropdown menus can now be positioned relative to their trigger elements without any JavaScript. The anchor() function and @position-try rules give you fallback positioning logic that the browser evaluates automatically when space is constrained.
Web Components in 2026
Web Components have matured significantly. With Declarative Shadow DOM now shipping in all major browsers, server-side rendering of custom elements is finally practical. The ElementInternals API gives custom elements access to form participation, validation, and accessibility features that were previously only available to built-in elements. Combined with CSS custom properties piercing shadow boundaries, the interoperability story is much stronger.
Optimizing Largest Contentful Paint
LCP remains one of the most important Core Web Vitals metrics. Key strategies include using fetchpriority="high" on hero images, preloading critical fonts, avoiding render-blocking CSS, and leveraging the browser's preload scanner. Server-side rendering or static generation can dramatically improve LCP by eliminating client-side rendering waterfalls. Inline critical CSS and defer everything else.
The State of CSS Nesting
Native CSS nesting has landed across all major browsers. Using the & selector, you can now nest rules inside parent selectors just like in Sass or Less. The relaxed parsing rules adopted in 2025 mean you can even start nested selectors with element names without needing the & prefix. This removes one of the last reasons many teams relied on CSS preprocessors for day-to-day authoring.
Scroll-Driven Animations Deep Dive
Scroll-driven animations tie CSS animation progress to scroll position rather than time. Using the animation-timeline property with scroll() or view() functions, you can create parallax effects, reveal animations, progress indicators, and sticky headers — all without JavaScript. The view() timeline is particularly elegant for entrance animations that trigger as elements scroll into the viewport.
Building Accessible Modals with the Dialog Element
The HTML dialog element with its showModal() method provides built-in focus trapping, backdrop rendering, and escape-key dismissal. Combined with the ::backdrop pseudo-element for styling and the close event for cleanup, you get a fully accessible modal pattern with minimal code. The Popover API complements this for non-modal overlays like menus, tooltips, and notification toasts.