Fix Uneven Spacing in Shopify Duplicate Themes

Hey everyone! As a Shopify migration expert and someone who spends a lot of time digging through community discussions, I often see common pain points that can really trip up store owners. One recent thread caught my eye because it touches on a surprisingly frequent issue: subtle visual discrepancies when you duplicate your Shopify theme.

We all know how crucial it is to have a staging environment or a duplicate theme for testing out new features, app integrations, or design tweaks without messing with your live site. It's a best practice, right? But what happens when your perfectly duplicated theme doesn't look exactly like the original, even before you make any changes? That's exactly what our community member, zidane11, ran into.

The Mystery of the Shifting Image

Zidane11 came to the community with a head-scratcher: every time they duplicated their store's theme, a specific image would show different spacing on the right side. On the live store, the image was perfectly centered with equal space on both sides. But in the duplicate, that right-side spacing was noticeably wider, making the image appear slightly smaller or shifted. This was happening immediately after duplication, with no changes made, and even AI tools weren't helping!

Here's what zidane11 shared, illustrating the difference:

And here's the duplicate, showing that extra space:

Community Weighs In: Initial Thoughts

Naturally, the first responses from community members like NKCreativeSoulutions and New_Dev focused on common culprits. Could it be a preview bar shifting the layout? (Zidane11 confirmed the dimensions looked the same in the inspector). What about an app embed or custom Liquid snippet causing a duplicate banner? (This was a good thought, but zidane11's issue was spacing, not a duplicate image itself).

Digging Deeper: The CSS Clue

The real breakthrough came when devcoders jumped in. They rightly pointed out that a Shopify duplicate should normally preserve theme code and settings. If spacing changes immediately, it almost always points to a CSS difference or a theme setting that's not translating correctly. Devcoders suggested comparing things like section/container width, padding, max-width, grid/flex settings, and any responsive CSS. They asked for the store URLs, which zidane11 promptly provided, enabling a direct comparison.

The "Aha!" Moment: Dynamic IDs

After reviewing the live and duplicated stores, devcoders pinpointed the exact issue. This is where it gets a bit technical, but it's super important for anyone doing custom CSS on Shopify. The problem wasn't a missing style, but rather how the style was being applied. The original store had a CSS rule tied to a section/block-specific ID:

#shopify-section-template--27436773998906__custom_content_fm4LAK .m-custom-content__block:last-child {
    padding-right: 0;
}

See that long, seemingly random string like shopify-section-template--27436773998906__custom_content_fm4LAK? That's a dynamic ID Shopify generates for each section. When you duplicate a theme, Shopify often regenerates these IDs. So, while the CSS rule was there in the duplicated theme's code, the specific ID it was targeting no longer existed, making the rule ineffective! Without that custom padding-right: 0;, the default padding kicked in, creating the extra space.

Laza_Binaery also spotted the critical CSS snippet, reinforcing that this was indeed the piece of code causing the trouble, even if the "why" was a bit elusive at first.

The Fix: A Robust CSS Rule

The solution, as devcoders brilliantly laid out, was to make the CSS selector more general, targeting the class instead of the dynamic ID. This way, it applies consistently, regardless of the section's unique identifier.

Step-by-Step Instructions to Resolve Spacing Differences:

If you're facing a similar issue where spacing goes awry after duplicating your theme, especially with custom CSS, here's how you can implement the fix:

Access Your Shopify Admin: Log in to your Shopify store admin panel.
Navigate to Themes: Go to Online Store > Themes.
Edit Code: Find the theme you're working on (likely the duplicated theme that has the issue). Click Actions > Edit Code.
Locate main.css: In the Assets folder, find the main.css file (or your theme's primary CSS file, it might be named theme.css or similar).
Add the Robust CSS: Scroll to the very bottom of the main.css file and paste the following code. This ensures the rule overrides any default styles and isn't tied to a dynamic section ID:
```
@media (min-width: 768px) {
  .m-custom-content__block:last-child {
    padding-right: 0;
  }
}
```
Save Changes: Click Save.
Check Your Duplicate Theme: Preview your duplicated theme again. The spacing should now be corrected!

Zidane11 confirmed that this solution worked perfectly, which is always great to hear!

Why This Matters for Your Store

This thread highlights a really important lesson for anyone doing custom development or using third-party apps on Shopify. While duplicating themes is an essential tool for testing, sometimes the underlying structure (like those dynamic Shopify section IDs) can cause unexpected visual glitches. Understanding that custom CSS tied to specific IDs might break during duplication can save you hours of head-scratching. Always aim for more general class-based selectors when possible, especially for global or section-wide styling, to ensure consistency across themes and updates.

It's a perfect example of how the community comes together to solve these tricky, specific problems that can make a huge difference in maintaining a consistent, professional-looking store. Keep testing, keep asking questions, and happy selling!

Solving the Shopify Duplicate Theme Spacing Mystery: A Community Deep Dive