Designing for a phone is straightforward: you have a rectangle, and you fill it. Designing for AI glasses is something else entirely. There is no screen, no blank page—only the world itself, in all its chaotic, vibrant, unbounded glory. How do you layer an interface onto that without overwhelming it?

Google's answer, after more than a decade of exploration, is Jetpack Compose Glimmer—a new design system for Android extended reality (XR) experiences, built specifically for transparent displays. And it required throwing out almost every assumption about what interface design means.

The Canvas That Isn't There

The first thing designers had to internalize: the interface doesn't actually sit on the lens. It's projected to a perceived depth of about one meter—roughly an arm's length away. That means to read anything, a user must consciously shift focus from the real world to this digital layer. It's an active choice, not a passive glance.

This became both the central constraint and the guiding opportunity. An interface on glasses has to earn that moment of attention. It has to be so helpful, so inviting, so gracefully integrated that users willingly choose to engage with it.

The Problem With Black

Early on, the team tried porting over familiar Material Design components. The result was a disaster. Material relies on opaque surfaces and shadows—paper metaphors that work on backlit screens. On an additive display, which can only add light, those "surfaces" became blinding blocks of glare. Black, which on a phone means "no light," on glasses means "completely transparent." It's not a color; it's a void.

Worse, bright surfaces created halation—a halo-like bleeding of light that made text illegible. The team had to redefine black entirely. In Glimmer, black is not a color but a container: a dark, rich surface that provides a legible foundation for content. Shadows, which traditionally suggest depth by darkening areas, had to be reimagined as exaggerated, opaque layers that create hierarchy without fighting the display physics.

Typography at Arm's Length

Text on glasses isn't measured in pixels or points. It's measured in visual angle—degrees of your field of view. Google's vision science team established a minimum readable size of about 0.6 degrees. Glimmer's typography sits comfortably above that, but size alone wasn't enough.

The team turned to optical sizing, tweaking Google Sans Flex to make individual letters more legible at a glance. Counters—the openings inside letters like 'a' and 'e'—are larger. The dots on 'j's and 'i's sit farther from the letter body. Letter spacing optimizes automatically. Every word is engineered to be readable the moment you shift focus to that one-meter plane.

Color That Doesn't Disappear

On a phone, you can use highly saturated colors and trust they'll be visible. Against a bright blue sky or a sunlit street, those same colors vanish. They become ghostly, illegible.

Glimmer solves this by going neutral by default. The interface harmonizes with the world rather than competing with it. Surfaces are always dark; content is always bright. This high-contrast baseline ensures legibility in most environments. Color is used sparingly and judiciously—a notification, a button, a moment that needs to draw attention—and when it is used, it's shifted toward white to maintain contrast against whatever backdrop the world provides.

Motion That Respects Attention

Because glasses are worn all day, content can appear at any time. It has to enter your field of view without startling you or demanding immediate focus.

Early prototypes used a 500-millisecond fade for notifications. The result was jarring: notifications seemed to blink into existence. The team slowed the transition to nearly two seconds, allowing the UI to drift gently from peripheral vision to center stage. It's motion that invites rather than demands.

But when a user actively provides input—a voice command, a gesture—responsiveness becomes critical. Glimmer uses instant focus rings and highlights to confirm actions, balancing ambient grace with immediate feedback.

The Philosophy

The throughline across all these decisions is a single idea: technology should enhance reality, not compete with it. Jetpack Compose Glimmer is designed to be ambient—present when needed, invisible when not. It's an interface that lives at the edge of perception, earning attention rather than extracting it.

As Google puts it: "We're excited for a future where helpfulness truly blends with reality, one graceful glance at a time."

The design system is available now, with a Figma Design Kit and documentation for developers building on Android XR.