In many sectors, most web traffic comes from mobile. If your site doesn’t adapt well to small screens, you lose visits, conversions and ranking. In this article we explain what responsive design is, why it’s essential and how to do it well.

What is responsive design?

Responsive design (or adaptive design) makes the same site look and work correctly on different screen sizes: mobile, tablet and desktop. It’s not about having “another version” for mobile, but the same code and content reorganising according to the space available. Menus, text, images and buttons adapt so the experience is usable on any device.

Responsive vs mobile-first

• Responsive: you design for desktop and then adapt to smaller screens with media queries and flexible layouts.
• Mobile-first: you design first for mobile (essential content, touch, speed) and then scale up for tablet and desktop. It usually gives better results on mobile and forces you to prioritise what matters.

In practice, mobile-first is the current recommendation: most users and traffic come from mobile, and Google indexes in mobile mode first.

1. Breakpoints and grids

Breakpoints are the screen widths at which the layout changes (e.g. 768px for tablet, 1024px for desktop). There’s no single standard; what matters is that between breakpoints the content doesn’t break or become unreadable.

Practice: use a grid system (CSS Grid or Flexbox) and relative units (%, rem, vw) instead of fixed pixels. That way elements adapt in a predictable way. Frameworks like Tailwind or Bootstrap define consistent breakpoints you can follow or customise.

2. Typography and readability

On mobile, long text in a small font is tiring and gets abandoned. Adequate font sizes (at least 16px for body text on mobile), comfortable line-height and sufficient contrast improve reading. Headings should hierarchy information clearly in limited space.

Practice: define a type scale (sizes for h1, h2, body, caption) and apply it consistently. On mobile, avoid very long lines (45–75 characters is often a good range) by using max-width on text containers.

3. Touch and interactive elements

On touchscreens, buttons and links must be easy to tap. Targets of at least 44x44px reduce errors and frustration. Don’t rely on hover alone for important information; on mobile there’s no cursor.

Practice: check menus, forms and buttons on a real device or emulator. Ensure spacing between tappable elements is enough and that nothing overlaps or is cut off.

4. Images and media

Images that look fine on desktop can be too heavy or badly framed on mobile. Responsive images (multiple sizes or srcset) and modern formats (WebP, AVIF) reduce weight and improve speed. Lazy loading avoids loading what isn’t visible yet.

Practice: serve images at the right size for each breakpoint, use picture/srcset or your framework’s options (e.g. next/image in Next.js) and compress without losing acceptable quality.

5. Mobile navigation

The desktop menu (many items in a row) usually doesn’t fit on mobile. Hamburger menus, accordions or bottom navigation are common solutions. Navigation should be visible, understandable and quick to use.

Practice: don’t hide what matters behind too many levels. Prioritise key sections and keep navigation consistent across pages. Test with real users if you can.

Conclusion

Responsive design isn’t optional: it’s the basis of a usable site that search engines and users value. Investing in coherent breakpoints, readable typography, adequate touch targets, optimised images and clear mobile navigation improves conversions and ranking. At Companies Webs every site we build is responsive and mobile-first; if yours isn’t adapted yet, it’s time to update it.