Sneaky Header Blocker Trick • Josh W. Comeau

A CSS-only technique for creating a sticky header that appears to change background color as the user scrolls through different page sections. Instead of modifying the header itself, two color-matched 'blocker' elements using position:sticky sit behind the fixed header — one in the hero section (blue) and one in the main content area (white). As the user scrolls, each blocker naturally exits its container, creating a seamless hand-off effect. The post also covers design constraints, how to integrate decorative SVG swoops into the layering, and when JavaScript fallbacks are necessary.