The Core Principle of Responsive Web Design (Explained with Real Experience Since 2019)

December 7, 2025

By Eventus Offiong Okon

Web Designer & Digital Strategist — Creating and optimizing websites since 2019.
When I first started learning web design in 2019, one of the biggest shocks I encountered was discovering that a website that looked beautiful on my laptop could look like a broken puzzle on a mobile phone. Text would overlap, images would stretch, columns would collapse — and clients would keep asking me, “Why is my website not the same on my phone?”That frustration pushed me to research, experiment, and eventually master responsive design. Today, after building dozens of websites for businesses across Nigeria and optimizing layouts across devices, I can confidently explain the real principle behind responsive web design — not the textbook definition, but what actually matters in real life.

So, What Is the Principle of Responsive Web Design?

The principle of responsive web design is that a website should automatically adapt to the user’s device, screen size, and orientation by using flexible layouts, flexible media, and CSS media queries.

In simple terms: a responsive website responds to the environment it is viewed in.

This principle is built on three major pillars:

  • Fluid Grids — layouts that stretch, shrink, and adjust.
  • Flexible Images & Media — visuals that scale without breaking.
  • Media Queries — CSS rules that apply specific designs at different breakpoints.

Every modern responsive website — whether coded manually or built with page builders — relies on these three principles working in harmony.

Why This Principle Matters in the Real World

You can design the most beautiful website in the world, but if it can’t adapt across phones, tablets, laptops, and large monitors, the design fails instantly. Over 75% of website visits in Nigeria today come from mobile phones, and as a designer who works with Nigerian clients every week, I see this firsthand.

Most people view websites from:

  • low-end Android phones
  • mid-range Android phones
  • iPhones
  • small tablets
  • laptops

If your design isn’t built responsively, you lose more than half your visitors immediately. That is why fully understanding the principle of adaptability is not optional — it is a survival skill for any designer or business owner online.

Let’s Break Down the Principle in Detail

1. Fluid Grids — The Structure That Adapts

Back when I started designing, I made the rookie mistake of using fixed pixel widths everywhere: 300px, 700px, 900px. Nothing was flexible. On mobile, it all collapsed.

The moment I understood fluid grids, everything changed.

A fluid grid uses proportional spacing instead of fixed pixels.

This means:

  • columns stretch or shrink depending on the device
  • containers adjust their width automatically
  • elements flow naturally instead of forcing fixed sizes

This is why designers use:

  • percentages (%)
  • viewport units (vw, vh)
  • Flexbox
  • CSS Grid

Real-life example:
A client once complained that their homepage text was “cutting out on the right side.” The issue? The content section was set to a fixed 1200px width. Changing it to max-width: 100% made the layout responsive instantly.

2. Flexible Images & Media — Because Visuals Break Layouts the Most

In 2019, I used large, uncompressed Canva images inside websites without resizing them. Every time a page loaded, the layout shifted because the images were too large or too fixed. That is when I learned the golden rule:

Images must scale automatically based on screen size.

The simplest responsive rule ever written is:

img {
  max-width: 100%;
  height: auto;
}

But beyond this, images must also be optimized. A 2MB image may look fine on a laptop, but on a small Android phone with poor network, it breaks both the layout and speed.

Now, I follow strict rules for every website I design:

  • export images from Canva at moderate sizes (max 1200px wide)
  • compress images before uploading
  • avoid fixed-height images
  • use responsive background images
  • allow video containers to scale with device width

This single change doubled the mobile usability scores of many websites I’ve designed.

3. Media Queries — The Brains Behind Responsive Behavior

If fluid grids and flexible images build a responsive layout, media queries turn it into a full adaptive experience.

A media query applies certain CSS only when specific device conditions are met — for example, screen width.

The most common example is:

@media (max-width: 768px) {
  .section-title {
    font-size: 24px;
  }
}

This allows designers to:

  • make text smaller on mobile
  • rearrange columns into stacked sections
  • remove non-essential elements on smaller screens
  • adjust spacing for readability
  • create mobile-only menus

Real-life experience:
A real estate website I built required a three-column property section on desktop. On mobile, I used media queries to stack the columns into a perfect one-column scroll. Clients loved the modern mobile look.

How the Principle Works in Real Design Scenarios

The core principle — adaptability — must guide every stage of the design process.

When designing the layout:

  • start with flexible units
  • avoid absolute positions
  • make sure columns can collapse

When adding media:

  • use proportionate images
  • compress files
  • ensure visuals scale fluidly

When writing CSS or adjusting a builder:

  • apply media queries where needed
  • test breakpoints manually
  • design mobile versions separately

Why Responsive Web Design Still Matters Today

Some people assume responsive design is no longer necessary because page builders handle it automatically. But as someone who works with websites daily, I can confidently say:

Page builders only give you the tools. Responsiveness requires understanding.

Even with tools like Elementor, Divi, Wix, or Canva Websites, you still have to:

  • set padding correctly
  • control mobile typography
  • ensure containers collapse properly
  • adjust row heights for small devices
  • optimize mobile navigation

Every website builder includes responsive settings because responsiveness is not optional; it is the foundation of modern web design.

Common Mistakes Designers Make (And How to Avoid Them)

After working with many new designers, I see the same mistakes repeatedly:

  • designing only for desktop first
  • ignoring mobile breakpoints
  • using large Canva images without compression
  • adding fixed sizes to everything
  • copying templates without customization
  • not testing on real phones

My advice is simple: test your website on the smallest device you can find.
If it works there, it will work everywhere.

The Tools I Use Today for Testing Responsiveness

  • Chrome DevTools — best for checking breakpoints
  • Responsively App — preview multiple devices at once
  • Real phones — low-end Android, iPhone, etc.
  • Canva — for mobile-friendly image exports
  • GTmetrix & PageSpeed Insights — to check mobile performance

No tool replaces real device testing. That is where you see the actual behavior of your layout.

Final Thoughts

The principle of responsive web design is simple but powerful:

Your website must adapt to the user, not the other way around.

Once you understand how flexible layouts, flexible media, and media queries work together, building responsive websites becomes easier — even enjoyable. Since 2019, this principle has guided every website I’ve built and taught me that responsiveness is not a “feature,” but a mindset.

If you want help converting this into a full cluster or need interlinking URLs for SEO, I’m ready.

Published by Taculia Designs