Feature 422 block design & features
The block pins to the viewport on large screens while the page scrolls through it, like the sticky chapters in feature423.
A centred heading and short line sit at the top. Below them, the chapters run across the page as a row of tabs. Each tab has a thin line above its title that fills continuously as you scroll through that chapter, so the row works as one segmented progress bar. The active tab's title and line darken.
Under the tabs, a wide product screenshot crossfades to match the active chapter, with separate light and dark images. Clicking a tab scrolls to the start of its chapter, with an instant jump under reduced motion.
Below the large breakpoint the block becomes a simple stacked list of chapters, each with its title, line and screenshot.