Programming Tutorials

  For years, the standard implementation for scroll-linked animations—parallax hero images, reading progress bars, and scroll-triggered fade-ins—has been imperative JavaScript. We attach listeners to the   window , calculate   scrollTop , normalize the value, and imperatively update DOM styles. Even with aggressive throttling, debouncing, or wrapping updates in  requestAnimationFrame , this approach suffers from a fundamental architectural flaw: it binds visual updates to the  Main Thread . On mobile devices with high refresh rate displays (90Hz+), the main thread is often busy parsing HTML, hydrating frameworks like React, or executing third-party scripts. When the main thread hangs, your scroll listener hangs. The result is "jank"—a visual stutter where the scroll momentum (handled by the browser's compositor) desynchronizes from the JavaScript-driven styles. The solution is to decouple scroll animations from JavaScript execution entirely using the CSS Scroll-...

  The "ragged footer" is one of the most persistent visual bugs in component-based web design. You have a row of pricing cards or feature teasers. The design mockup shows perfectly aligned titles, descriptions, and "Buy Now" buttons. In implementation, reality hits. One title wraps to two lines. One description is slightly longer. Suddenly, your "Buy Now" buttons are scattered at different vertical positions, destroying the visual rhythm of the row. For years, we hacked this. We used JavaScript to equalize heights ( matchHeight.js ). We used  min-height  with magic numbers. We used Flexbox with  margin-top: auto  on the footer to force it to the bottom of the card. While  margin-top: auto  aligns the  bottom  of the footers, it does not align the  start  of the footers if the footers themselves vary in height, nor does it align the internal sections (like headers) across the row. With CSS Grid Level 2 (Subgrid), we can solve this la...