Designing for Every Direction: Logical CSS for Global, Adaptive, and Effortlessly Reversible UIs

As the web becomes increasingly global, modern UIs can no longer assume left-to-right text, fixed layout directions, or static component structures. Interfaces today must support internationalisation, RTL languages, vertical writing systems, and dynamic layouts that reflow across responsive dashboards and design systems. In this talk, we explore how Logical CSS enables a fundamentally more resilient approach to UI architecture. You’ll see how properties like margin-inline, border-block, and inline-size allow layouts and components to adapt automatically to writing direction, writing mode, and layout orientation - without duplicating styles or introducing fragile overrides. Through real-world examples, we’ll look at supporting Arabic and Hebrew, enabling vertical Japanese layouts, designing components that flip seamlessly as layouts change, and building design-system primitives that remain stable across products, regions, and use cases. We’ll also cover practical migration strategies, local testing techniques, and the mindset shift from physical directions to flow-based design. Whether you’re building a global application, maintaining a design system, or planning for the long-term evolution of your UI, this session will help you create future-proof, direction-agnostic interfaces - designed for every direction.