1.1 Missing or Poorly Written Media Queries

Media queries tell your website how to behave on different screen sizes. If they’re missing or incorrectly written, the layout won’t adapt.

For example:

@media (max-width: 768px) {  
.container {
    width: 100%;
    }
}

Without rules like this, your desktop layout simply shrinks down, leaving content squashed or overflowing.

How to prevent it:
Make sure your theme or builder uses responsive breakpoints, and avoid custom CSS that overrides them unintentionally.

1.2 Fixed Elements That Don’t Scale

Designers sometimes use fixed widths, fixed heights, or fixed positioning to achieve specific effects. On mobile, these elements don’t shrink or move correctly, causing overlapping sections or disappearing content.

For example, a fixed element like:

width: 500px;

won’t fit on a 375px-wide phone.

How to prevent it:
Use percentage-based widths or responsive utility classes that adapt to screen sizes.

1.3 Overlapping Elements and Z-Index Issues

Sometimes layers overlap in unexpected ways because of incorrect z-index values. A button might be hidden behind an image, or text may appear behind a coloured background.

How to prevent it:
Review your stacking order and avoid unnecessary absolute positioning (more on that below).

3.1 Hidden Desktop Settings Without Mobile Overrides

Many builders allow you to change font sizes, padding, margins, and alignment separately for desktop, tablet, and mobile.

If you only adjust desktop settings, the mobile version inherits them – even when they don’t fit properly.

3.2 Too Many Columns

A four-column layout on desktop might look lovely. On a mobile screen, those four columns stack into a long vertical list. If each column contains large images or text, it becomes overwhelming and slow.

3.3 Builder-Specific Bugs

Some builders render differently across devices. For example:

• Elementor sometimes duplicates spacing.
• Divi occasionally ignores mobile padding.
• Gutenberg block patterns break if custom CSS is applied.

How to prevent it:
Always check each builder’s mobile preview and test on real devices.

4.1 Absolute Sizing

Absolute values force elements to stay a specific size or position, for example:

• px (pixels)
• fixed positioning
• specific heights or widths

While fine for desktop, they break on smaller screens.

4.2 Relative Sizing

Relative values adapt based on the screen size:

• % (percentage)
• rem / em
• vh / vw
• auto spacing

Using responsive units ensures text, images, and sections scale naturally.

How to prevent it:
Avoid fixed values unless absolutely necessary. Focus on flexible units that respond automatically.

5.1 Incorrect Image Aspect Ratios

If the container for the image is square but the image is rectangular, it will crop or stretch on mobile.

5.2 Large Images Slowing Down Mobile Performance

Mobile users on poor signal connections struggle to load large images. Slow loading often causes layout shifts and broken sections.

5.3 Background Images Without Fallbacks

Some designs use background images that don’t scale properly, making text unreadable.

How to prevent it:

• Use responsive image ratios
• Optimise images for smaller screens
• Avoid text on background images
• Test in portrait and landscape orientation

Step 1: Check Your Theme for Mobile Compatibility

Start by confirming that your theme supports responsive design.

What to look for:

• When was the theme last updated?
• Does the theme have a responsive grid system?
• Does it offer separate mobile controls?

If the answer is “no”, your theme may be the root cause of your mobile issues and upgrading to a modern mobile-first theme (Astra, Blocksy, GeneratePress, or a Gutenberg theme) is often the quickest fix.

Step 2: Test the Page Without Your Page Builder

Sometimes the builder causes the problem.

How to test:

• Create a blank page
• Add a single text block using your theme’s default editor
• Preview it on mobile

If this test page works but your designed pages don’t, the issue is likely caused by your page builder’s settings, column layouts, or mobile overrides.

Step 3: Inspect Custom CSS

Poorly written CSS is one of the biggest reasons small businesses ask “why website is not mobile friendly?”

Check for:

• Fixed widths (e.g., width: 500px;)
• Large margins or padding
• Absolute positioning
• Desktop-only font sizes
• Missing media queries

If something looks too rigid, it will almost always break on mobile.

Step 4: Review Your Column Layouts

Open your page builder’s mobile preview and check how columns stack.

Ask yourself:

• Are there too many columns?
• Are the images too wide?
• Is the spacing too tight or too large?
• Are items stacking in the wrong order?

Adjust your layout so mobile users get a clean, single-column experience.

Step 5: Test Your Navigation Menu

Navigation often behaves differently on mobile:

Look for:

• Hidden burger icons
• Menu items overlapping
• Dropdowns that don’t close
• Full-screen menus covering content

Fixing mobile navigation dramatically improves user experience.

Step 6: Check Image Sizes and Ratios

Images often break layouts when:

• Their aspect ratio doesn’t match the container
• They’re too large for mobile screens
• They’re set with fixed heights or widths
• Background images crop badly

Switching to consistent ratios (e.g., 16:9, 4:3, 1:1) solves most issues.

Step 7: Remove Excessive Padding and Margins

Large spacing looks fine on desktop but causes disasters on mobile.

Check:

• Top and bottom padding on hero sections
• Left and right margins on text
• Spacer blocks or empty columns

Reduce padding by at least 50% for mobile.

Step 8: Disable Plugins One by One

Sometimes a plugin injects CSS or scripts that conflict with your layout.

Test your site while deactivating plugins individually, especially:

• Sliders
• Pop-ups
• Animation libraries
• Page-building add-ons

If your layout suddenly works, you’ve found the culprit.

Step 9: Test on a Real Device

Builder previews aren’t always accurate.
Before making final changes, check the site on:

• An iPhone
• An Android device
• Chrome, Safari, Edge
• Portrait and landscape modes

Real-device testing reveals issues you won’t spot in a simulator.

Step 10: Run a Google Mobile-Friendly Test

Use Google’s own tool to confirm your site meets mobile standards:
search “Google Mobile-Friendly Test”

It will highlight problems like:

• Text too small
• Clickable elements too close
• Content wider than screen
• Resources blocked

Fixing these improves your SEO and user experience.