A dark landing page won our A/B test – here’s why best practices got it wrong

I expected the dark-themed landing page to lose. 

Everything I knew about conversion optimization said the light background should win. 

Light themes are standard for B2B lead generation pages because they offer better readability, cleaner visual hierarchy, and align with accessibility standards. 

Unbounce’s analysis of 41,000 landing pages establishes baseline patterns favoring light backgrounds. It seemed like a safe bet.

But after splitting paid traffic 50/50 between a dark landing page and a light landing page for our industrial fleet repair SaaS, the light variant achieved a 16.62% higher CTR yet delivered 42% fewer total conversions.

This isn’t an argument for universal adoption of dark themes. 

It’s a case study in why audience context and industry-specific psychological associations matter more than following aggregate best practices derived from different populations.

Why light seemed like the obvious choice

We operate in a niche B2B SaaS vertical serving the transportation industry – specifically businesses that maintain commercial vehicles and equipment. 

Our target buyers are shop owners and operators who spend their days in industrial environments managing technicians, equipment, and demanding commercial customers.

Going into this test, I had specific expectations.

• Light backgrounds would convert better for text-heavy lead generation pages. Professional B2B landing page design principles emphasize whitespace and visual hierarchy. For our 7-field form targeting busy shop operators, light mode with dark text should provide superior readability.
• Blue CTAs would outperform. Blue is commonly associated with trust and security, which are critical for B2B software purchases. Our treatment used a blue CTA button for this reason.

I was wrong on both counts.

Dig deeper: 5 tips for creating a high-converting PPC landing page

The test: Isolating visual design

We ran a standard 50/50 split test through Google Ads and Meta, directing traffic to two landing pages with identical copy but drastically different visual presentations.

The control featured a dark theme: 

• Black background throughout.
• White text overlay.
• High-contrast white form fields on the dark backdrop.
• A black CTA button with a red outline.
• A dark overlay on the background image (trucks and an industrial environment). 
• No brand logo in the header.

The treatment used a light theme: 

• White and light gray background.
• Dark text on the light background.
• Light gray form fields on white.
• A blue CTA button.
• A lighter overlay on the same background image. 

The brand logo was prominently displayed in the header.

We kept everything else identical, particularly the:

• Headline.
• Body copy. 
• Value proposition. 
• 7-field form structure (email, name, business name, phone, shop type, technician count). 
• Page layout. 

This variable isolation is critical. If you change multiple elements, you cannot attribute results to any single change.

The test ran for 3 to 4 weeks on Google Ads search campaigns and Meta (Facebook and Instagram). 

The total spend on Google was $8,205.97, resulting in 767 clicks and 30 conversions.

What happened: The light theme’s CTR advantage was misleading

The results from Google Ads:

Dark theme:

• 10,250 impressions.
• 466 clicks (4.55% CTR).
• 19 conversions (4.08% conversion rate). 
• Cost per conversion: $274.67.

Light theme: 

• 5,677 impressions (44.6% fewer). 
• 301 clicks (5.30% CTR).
• 11 conversions (3.65% conversion rate). 
• Cost per conversion: $271.56.

The light theme’s CTR was 16.62% higher, which would typically be interpreted as a win. 

But it attracted lower-quality traffic that converted at comparable or worse rates. 

Meanwhile, Google’s algorithm allocated 44.6% fewer impressions to the light variant, resulting in 42% fewer total conversions despite essentially identical cost per conversion.

We ran the same test simultaneously on Meta, and the results were even more definitive. 

The dark theme significantly outperformed the light theme in conversions, with the light variant rarely generating conversions at all. 

This cross-platform consistency suggested the finding wasn’t an algorithmic quirk – it was an audience preference.

Metric	Control (Dark)	Treatment (Light)
Impressions	10,250	5,677 (-44.6%)
Clicks	466	301 (-35.4%)
CTR	4.55%	5.30% (+16.62%)
Conversions	19	11 (-42.1%)
Conversion Rate	4.08%	3.65% (-10.5%)
Cost per Conversion	$274.67	$271.56 (-1.1%)

Note: Google’s algorithm allocated significantly fewer impressions to the light theme, likely detecting lower engagement signals that affected Quality Score.

Dig deeper: Dynamic landing pages: What works, what fails, and how to test

Why the dark theme won: Audience psychology over design theory

The result makes sense when you consider who we’re targeting and what they respond to psychologically.

Identity alignment: ‘This is for people like me’

Commercial transportation businesses are industrial workplaces. 

The aesthetic is functional, not decorative. Dark colors, metal surfaces, concrete floors, and equipment with black housings. 

The environmental psychology of these spaces shapes what feels trustworthy to the people who work in them.

The dark landing page matched that identity. It signaled “built for your industry” without explicitly stating it. 

The light theme, with its clean, modern aesthetic and prominent branding, resembled consumer SaaS: professional, polished, and aimed at someone else.

This pattern consistently appears in optimization testing: designs that reflect the visitor’s environment convert better than those that aspire to a different aesthetic standard.

Form contrast: Making interaction obvious

The white form fields on the dark background created exceptional contrast. They were visually unmissable. 

The form demanded attention not through size or position, but through contrast that made it impossible to ignore.

The light theme’s gray-on-white form fields blended into the page. They required conscious visual search. 

For a 7-field B2B form targeting busy shop operators, reducing cognitive load through clarity matters more than aesthetic refinement.

Tonal weight: Seriousness signals value

Dark backgrounds communicate weight, substance, seriousness, and luxury. They feel significant. 

Light backgrounds communicate ease, accessibility, and friendliness. 

All valuable qualities for many products, but potentially wrong for expensive B2B software aimed at industrial buyers.

Industrial software is a significant operational investment. It touches every part of the business: scheduling, invoicing, inventory, and customer relationships. 

Buyers need to feel that the software is substantial enough to handle that responsibility. 

The dark theme’s visual gravity supported that perception. The light theme’s brightness worked against it.

Category conventions: The familiar is trustworthy

Most heavy equipment, repair tools, and industrial software use dark interfaces. 

Parts catalogs, diagnostic software, and inventory systems typically trend toward dark themes with high-contrast elements. 

This isn’t random. It’s a category convention that has emerged because it works in these contexts.

Category conventions matter. Violating them can signal innovation, but it can also signal unfamiliarity. 

For risk-averse buyers making expensive B2B purchases, the familiar aesthetic reduced perceived risk rather than creating it.

The CTA color lesson

Despite following best practices by using a blue CTA button on the light theme (the color associated with trust in B2B contexts), it underperformed against the black button with red outline on the dark theme.

This violated conventional color psychology, but the explanation is straightforward: contrast matters more than color choice. 

The black-and-red button created a dramatic contrast against the dark background and white form fields, making it impossible to miss. 

The blue button, while theoretically the “correct” choice, blended into the light design’s overall aesthetic, reducing its visual prominence despite proper color selection.

Dig deeper: How to design landing pages that boost SEO and maximize conversions

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The real lesson: Test design psychology, not just design

The lesson isn’t “dark beats light.” 

It’s that design is a carrier for psychological signals that vary by context. 

Your test hypothesis should be about the message your design sends, not the design itself.

Before your next test, ask:

• What does this design signal about who the product is for? Does it match your buyer’s identity, or create distance?
• What emotional response does it create? Weight/seriousness versus lightness/ease? Trust versus skepticism? Familiarity versus novelty?
• How does it fit category conventions? Are you violating expectations intentionally (differentiation) or accidentally causing confusion?
• What does it demand of the visitor? Does high contrast reduce cognitive load, or does darkness create strain?
• How does it connect to the previous step? Are you maintaining aesthetic continuity from ad/email/referral source?

These questions matter more than “which color converts better” because the answer to that question is always “it depends.”

Dig deeper: PPC landing pages: How to craft a winning post-click experience

How to run your own landing page design test

If you want to run a similar experiment, here’s what I learned about proper test structure.

Create true visual opposites

Don’t test shades of the same approach. Develop genuinely distinct aesthetic treatments that represent unique psychological perspectives. 

Dark versus light is a clear contrast. Light blue versus light green is not.

Keep everything else identical

Same copy, form, value prop, CTA, page structure, and URL parameters. Change only the visual treatment. 

If you change multiple variables, you can’t attribute results to any single change. 

Proper A/B testing requires variable isolation to draw valid conclusions.

Monitor both ad and landing page performance

Track CTR separately from conversion rate. 

If one variation gets higher CTR but lower conversion rate, you’ve discovered a message-match problem – the ad is attracting the wrong traffic.

Also, monitor if Google’s algorithm allocates impressions differently. 

If one variation gets significantly fewer impressions, the algorithm may be detecting lower quality scores or engagement signals.

Calculate true cost per conversion

Don’t just compare conversion rates. 

Calculate actual cost per conversion including ad spend. 

A variation with slightly lower conversion rate but significantly lower CPC might win on efficiency.

Look at confidence intervals, not just point estimates

With smaller conversion volumes, confidence intervals matter more than point estimates. 

The conversion rates were too close to call a definitive winner based on the sample size. 

Consider audience segmentation

If possible, segment results by device, geography, time of day, or other demographic factors. 

Dark themes might perform differently for mobile versus desktop, or for different age ranges.

Run qualitative analysis

Use heatmaps to see where users focus attention on each variation. Run session recordings to watch actual navigation behavior. 

Survey converters and non-converters to understand perception differences. We didn’t do this for this test, but it would strengthen the analysis significantly.

Dig deeper: Audience targeting in Google Ads Search campaigns: How to layer data for better results

Why audience context trumps best practices

The dangerous part of best practices in optimization is the implicit universality claim. 

“Light backgrounds convert better” becomes “light backgrounds always convert better for everyone,” which leads to cargo cult optimization, copying tactics without understanding context.

Light backgrounds do tend to outperform in aggregate data. But averages hide variation. Industry-specific contexts reveal massive differences. 

What works for SaaS doesn’t work for events. What works for ecommerce doesn’t work for B2B services.

Your optimization framework should start with “who is my audience and what signals do they respond to?” – not “what does research say works on average?”

The most successful tests challenge assumptions rather than confirm them. 

This test challenged the assumption that modern, clean, light design is universally superior. It wasn’t, at least not for this audience.

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Clarity in your tests creates clarity in your decisions

Industrial B2B is just one example, but the principle holds everywhere: design only works when its signals match the audience. 

When you ground your tests in that question – not in aesthetics – you get cleaner data and clearer decisions. 

That shift turns every experiment into a reliable read on what your audience actually values, and that’s what drives consistent, defensible gains over time.