The Art of Glassmorphism: Building Modern Interfaces

Modern design is evolving beyond flat surfaces. With glassmorphism, we can create interfaces that feel layered, dimensional, and alive — while maintaining excellent readability and accessibility. This article walks through the principles, techniques, and pitfalls of adopting glassmorphism in production interfaces.

What Is Glassmorphism?

Glassmorphism is a design language built around frosted glass effects. It uses background blur, semi-transparent layers, and subtle borders to create a sense of depth without resorting to heavy shadows or 3D transforms.

The key properties are:

• Background blur — typically backdrop-filter: blur(16–40px)
• Translucent fills — backgrounds using low-alpha HSL values
• Subtle borders — 1px lines at very low opacity to define edges
• Layered depth — multiple glass panes stacked to create hierarchy

When combined, these create a UI that feels physical and modern, similar to the aesthetic Apple introduced with macOS Big Sur and continued with iOS.

Core CSS Techniques

At its simplest, a glass card can be built with just a few properties:

.glass-card {
  background: hsl(0 0% 100% / 0.08);
  backdrop-filter: blur(24px);
  border: 1px solid hsl(0 0% 100% / 0.12);
  border-radius: 1.25rem;
}

However, production-quality glass requires more nuance. You need to handle:

1. Fallback for browsers without backdrop-filter — use a solid background as the base
2. Performance — blur is GPU-intensive; limit the number of blurred layers
3. Contrast — ensure text remains readable against any background
4. Theme adaptation — glass must work on both light and dark backgrounds

Designing for Accessibility

One of the biggest challenges with glassmorphism is maintaining sufficient contrast ratios. Transparent backgrounds mean your text sits over whatever content is behind the glass, which can vary wildly.

Strategies

• Use a higher alpha value for the background (e.g., 0.6 instead of 0.08) when contrast is critical
• Add a secondary solid layer beneath the glass for important interactive elements
• Test with WCAG contrast checkers against the worst-case background
• Use text shadows or outlined text sparingly to improve readability in edge cases

Glassmorphism should enhance the experience, not compromise it. If blur reduces readability, increase the background opacity until the text passes WCAG AA contrast.

Theme-Aware Glass

In our design system, glass effects automatically adapt to the current theme. Instead of hardcoding colors, we use CSS custom properties:

.themed-glass {
  background: hsl(var(--b2) / 0.4);
  backdrop-filter: blur(20px);
  border: 1px solid hsl(var(--bc) / 0.08);
  color: hsl(var(--bc));
}

This means the same glass component renders beautifully whether the user has selected a dark, light, or color-shifted theme — without any JavaScript toggling.

Animation and Micro-Interactions

Glass surfaces come alive with subtle animations:

• Hover glow — shifting a radial gradient on hover to simulate light reflection
• Depth shifts — slightly increasing blur and shadow on interaction
• Entry animations — fading in with a backdrop-filter transition

.glass-card {
  transition:
    transform 0.4s cubic-bezier(0.32, 0.72, 0, 1),
    box-shadow 0.4s ease;
}

.glass-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 20px 50px hsl(var(--bc) / 0.1);
}

Performance Considerations

backdrop-filter triggers GPU compositing. On lower-end devices or pages with many overlapping glass elements, this can cause:

• Janky scrolling — the GPU has to re-composite blurred regions every frame
• High battery drain — especially on mobile
• Paint storms — when glass overlaps other animated elements

Mitigations

Building a Glass Component Library

When building a component library with glassmorphism, establish a glass token system:

1. Glass Light — blur: 12px, bg: 0.04 alpha — for subtle hover states
2. Glass Medium — blur: 20px, bg: 0.08 alpha — for cards and containers
3. Glass Heavy — blur: 40px, bg: 0.15 alpha — for modals and overlays
4. Glass Solid — blur: 40px, bg: 0.6 alpha — for navigation and critical UI

This gives designers consistent vocabulary while allowing engineers to implement predictable, performant glass effects.

Glassmorphism is more than a trend — when used thoughtfully, it creates interfaces that feel premium, layered, and modern. The key is balancing aesthetics with accessibility and performance. Start with solid fallbacks, test contrast rigorously, and keep your glass layers minimal.