The split-screen theme for OpenCart 4: from 1024 px a fixed panel on the left half shows the campaign slides, the category with its subcategories, the own images of the product or the brand, while the shop scrolls on the right. Eight duotone colour schemes (two dark) plus your own colours, editorial serif headings with numbered sections, three home layouts (Duo, Story with department chapters, Classic without the split), mega menu, live search, quick view, AJAX filters, sticky add-to-cart and a one-click Twofold demo store. Events only, no core changes, no OCMOD.
Tested on 4.1.0.4Version 1.0.1Compatible with OpenCart 4.1.0.0 – 4.1.0.4 No core file edits
Duo, Linen scheme: campaign slides in the fixed left panel, the shop on the right, on desktop and phone1 of 11
What it does
The split-screen theme for OpenCart 4: from 1024 px a fixed panel on the left half shows the campaign slides, the category with its subcategories, the own images of the product or the brand, while the shop scrolls on the right. Eight duotone colour schemes (two dark) plus your own colours, editorial serif headings with numbered sections, three home layouts (Duo, Story with department chapters, Classic without the split), mega menu, live search, quick view, AJAX filters, sticky add-to-cart and a one-click Twofold demo store. Events only, no core changes, no OCMOD.
Features
Home: campaign slides in the panel with a product packshot and its "from" price, or your own photo, a serif headline with one italic accent word, two buttons, a counter and a progress bar.
Category pages: the category image, name, product count, description and subcategory chips in the panel; filters open as a drawer.
Product pages: the product's own images as a vertical stack with a counter; choosing a colour scrolls to its image; the buy box never moves; sticky add-to-cart bar.
Brand pages: logo, name and product count in the panel.
3 home layouts: Duo (numbered sections), Story (numbered department chapters) and Classic (no split, full-width slider). Category and product pages can split or stay full width.
Home sections: service strip, shop by category, Picked for you tabs, The edit (shop the look), deals band with a live countdown, brands, customer reviews, journal and about, newsletter card.
8 duotone colour schemes: Linen, Sage, Coast, Blush, Citrus, Lilac and the dark Noir and Tide, plus four colours of your own; text colours follow and are corrected for contrast (4.5:1 in all eight schemes).
Shopping: mega menu with a featured product, live search, quick view, compare, wish list, AJAX filters and sorting with Show more, grid and list views, deal countdowns, quantity prices, delivery dates, phone bottom bar, structured data.
One-click demo store: Twofold, 40 illustrated technology products with colour and storage options; it arrives on a fresh store and leaves with one click.
OpenCart 4.1.0.0 to 4.1.x. Events only: no core changes, no OCMOD. Self-hosted fonts, no CDNs.
Duo next to our other OpenCart themes
Every Kavio Labs theme has its own character. This table shows where Duo differs, so you can pick the one that fits your store.
Duo compared with our other OpenCart themes
Duo
Atlas
Vertex
Volt
Prism
Price (one-time)
$69
$129
$149
$59
$99
Signature
Split screen: a fixed context panel on the left half, the shop scrolls on the right
Department store with colour lines per department
The theme you configure: headers, homes and product pages in the settings
Electronics superstore with spec meters
Five store styles in one package
What the panel / hero shows
Campaign slides, the category, the product's own images, the brand
Rail of departments beside a slider
Stage with a promotion strip
Deal stage with spec callouts
Per style
Colour schemes
8 duotone pairs (2 dark) + colour editor
4
16 + colour editor
4
5 styles
Home layouts
3 (Duo, Story with chapters, Classic)
1
3
1
1 per style
Type
Playfair display + Epilogue, numbered sections
Schibsted + Onest
Mona Sans
Sora + Inter
6 families
Product page
Image stack in the panel that follows the colour choice, sticky add-to-cart
3 columns + sticky buy box
Studio, Cascade or Compact
Lab score rings
Per style
OpenCart versions
4.1.0.0 – 4.1.x
4.x + 3.0.x
4.x + 3.0.x
4.x + 3.0.x
4.x + 3.0.x
Demo store
Twofold (technology, 40 products)
Atlas Market
Circuit Hall
Nodal Electronics
5 stores
What you get
Download & installOne installer package (.ocmod.zip) for OpenCart 4.1.0.0 – 4.1.x. There is no OpenCart 3 edition. Download it from My licenses right after payment.
12 months of updates & supportNew versions and help for 12 months (24 or 36 months at checkout). After that the theme keeps working; renew anytime at 50%.
License for your storeOne production domain with all its subdomains; staging and local development hosts are free. How licensing works
30-day refundFull refund within 30 days of your first purchase, no reason needed. Refund policy
Tested buildsOpenCart 4.1.0.0 – 4.1.0.4. Tested on OpenCart 4.1.0.4.
Documentation & supportFull guide (Installation, Configuration, FAQ) on this page. Tickets from your account, first reply within 1 business day.
Compatibility
Duo: Split-Screen Theme works with OpenCart 4.1.0.0 – 4.1.0.4.
We list the builds we install and test on. “Tested” means the test plan ran on that build; “Supported” means the build is inside the supported range.
Compatibility
Version
Range
Runs on
Status
OpenCart 4.1.0.x
4.1.0.0 – 4.1.0.4
PHP 8.1 – 8.3
Tested on 4.1.0.4
1.0.1
Latest
Product cards show the product's own stock status at quantity 0 (Pre-Order, 2-3 Days, In Stock ...) on OpenCart 4.1, as the product page does; "Sold out" only when the product has no stock status. Checkout without stock still decides whether the card can be added to the cart.
A store name with "&", quotes or "<" in the header and footer logo text shows as typed (it was shown as "&").
Updates keep the theme settings and the licence key: OpenCart 4 deletes them before an update's uninstall, Duo now keeps a copy and puts it back on install, and stores that used Duo use it again. Updating from 1.0.0: see the documentation (Installation > Update).
The menu cache is cleared once per product or category save (it was cleared for every sub-step of a save) and lasts 15 minutes, so a special that starts or ends shows in the menu soon.
The home page builds only the six deal cards it shows.
The campaign text without slides uses the store's meta description of the current language.
Accessibility: the page content sits inside the main landmark, the slide carousels are labelled regions, the product tabs are labelled with the section title, and a slide never puts a hidden link back into the tab order.
1.0.0
First release for OpenCart 4.1.0.0 – 4.1.x: the OpenCart edition of the Kavio Labs split-screen flagship Duo.
Split context panel from 1024 px: campaign slides on the home page, the category (image, description, subcategory chips, product count), the product's own images as a scrolling stack with counter, keyboard steps and zoom, the brand.
Three home layouts: Duo, Story (numbered department chapters) and Classic (no split, full-width slider).
Eight duotone colour schemes (Linen, Sage, Coast, Blush, Citrus, Lilac, Noir, Tide) plus a colour editor (action, panel, pop and paper colours; text colours follow and are corrected for contrast, 4.5:1 in all eight schemes).
Home sections: service strip, shop by category, picked for you (tabs), the edit (shop the look), deals band with a countdown, brands, customer reviews, journal and about, newsletter card, store story and chapters.
Mega menu, live search, quick view, compare, wish list, AJAX filters and sorting with show more, sticky add-to-cart bar, structured data, mobile bottom bar.
One-click Twofold technology demo store (40 products, options, specials with end dates, reviews, journal); removable.
Events only: no core changes, no OCMOD.
How do I install the theme?
Download the package from My licenses and install it in Extensions > Installer, then Extensions > Themes, like any other OpenCart theme. The Documentation tab has every step, from the first activation to the theme settings.
Which OpenCart versions does it work with?
OpenCart 4.1.0.0 – 4.1.0.4. Tested on OpenCart 4.1.0.4. The Compatibility tab lists every version range.
What does the license cover?
One production store domain with every subdomain (www, shop., staging.), plus local development hosts such as localhost, *.local and *.test. A store on another domain needs its own license; a second-store license is 40% off. You have 14 days after installing to enter the key. 12 months of updates and support are included; after that the theme keeps working and renewals are 50% off. How licensing works
Can I get a refund?
Yes. Ask for a full refund within 30 days of your first purchase, no reason needed: open a ticket or write to [email protected] with your order number. The money goes back to the card or bank account you paid with within 5 business days of approval. Refund policy
How do I get help?
Open a ticket from your account, so your license details are attached. We answer Monday to Friday: bug reports within 1 business day, how-to questions within 2. Support policy. Not a customer yet? Ask a pre-sales question.
Duo is a flagship theme of Kavio Labs for OpenCart 4.1.0.0 to 4.1.x, the OpenCart edition of the Duo theme for CS-Cart. Its idea is the split-screen store: from 1024 px a fixed context panel fills the left half of the screen while the shop scrolls on the right. The panel follows the page: campaign slides on the home page, the category with its subcategories, the product's own images as a scrolling stack, the brand. Phones get a clean one-column store.
It is one universal design for every sector: technology, fashion, home, beauty, gifts or a single-brand store. The demo is a technology store, Twofold.
Duo home page, Linen scheme
What you get
The split context panel (1024 px and wider; 42 % of the screen up to 1279 px, half from 1280 px):
Home: campaign slides with a product packshot in a ring and its "from" price, or your own photo; numbered label, serif headline with one accent word, two buttons, arrows, counter and a progress bar. Autoplay pauses on hover, focus and touch.
Category: the category image (or a big serif initial), name, product count, the first sentence of the description and subcategory chips.
Product: the product's images as a vertical scroll-snap stack with a counter and dots; arrow keys step, a click opens the large image, choosing a colour moves the stack to the image named after that colour. The buy box never moves.
Brand: logo or initial, name and product count.
Three home layouts in the settings: Duo (slides in the panel, numbered sections on the right), Story (slides in the panel, numbered department chapters) and Classic (no split: a full-width slider, then the sections). Category, product and brand pages can split or stay full width (one switch).
Home sections, numbered in order ("01 / Shop by category"): service strip, shop by category tiles, Picked for you tabs, The edit (a scene card with the products that go with it), a deals band with a live countdown, brands, customer reviews (your latest 4 and 5 star reviews), journal and about, newsletter card, store story and department chapters.
Eight duotone colour schemes: Linen, Sage, Coast, Blush, Citrus, Lilac and two dark ones, Noir and Tide. Each scheme pairs the paper of the shop with the coloured ground of the panel. Four colours of your own (action, panel, pop and paper); text colours follow by themselves and are corrected for contrast (every text pair of the eight schemes reaches 4.5:1).
Editorial type: Playfair for headings (one word in stars becomes the italic accent), Epilogue for text, hairline rules, small caps labels, near-square 6 px cards without shadows and pill buttons.
Mega menu: top categories with a panel of subcategories, counts and a featured product; departments that do not fit go into "More"; a drawer menu on tablets and phones.
Shopping: live search with product and category suggestions, quick view, compare, wish list, AJAX filters and sorting with Show more, grid and list views, deal countdowns on cards, quantity prices, sticky add-to-cart bar, delivery dates, a phone bottom bar.
One-click demo store: Twofold (eight departments, 40 illustrated products of six invented brands with colour and storage options, specials with end dates, reviews and journal articles).
Structured data (JSON-LD): product, offer, rating and breadcrumbs; the store and its search box on the home page.
Safe and fast. Events only: no core file changes, no OCMOD. Self-hosted fonts (SIL Open Font License 1.1), one stylesheet and one script, no CDNs.
Requirements
OpenCart 4.1.0.0 to 4.1.x (tested on 4.1.0.4)
PHP 8.1 or later (what OpenCart 4.1 needs; the theme code itself runs on PHP 7.4+)
Pages
Installation
Go to Extensions > Installer and upload kv_theme_duo.ocmod.zip. Click Install (the green + button) next to it.
Go to Extensions > Extensions, choose the type Themes, and click Install next to Duo Theme by Kavio Labs.
Click Edit, check that Status is on, pick a Colour scheme and a Home page layout and save.
Go to System > Settings, edit your store, and on the General tab set Theme to Duo Theme by Kavio Labs. Save.
OpenCart 4 has no theme folders. Duo is a theme extension: it swaps in its own templates while it is the store theme and switched on. Switch the store back to Default to return to the stock look at any time.
Recommended image sizes (System > Settings > Image): product card 600 x 600, product page 1000 x 1000, popup 1400 x 1400, additional 160 x 160, cart 140 x 140, category 600 x 600. Square packshots on a white or transparent background look best: Duo shows them on a light plate, also in the dark schemes.
Duo is built for OpenCart 4 (Bootstrap 5). There is no OpenCart 3 edition.
The demo store
On a fresh store (no products, or only the OpenCart sample products and no orders) the install adds the Twofold demo: eight departments, 40 illustrated products with colour and storage options, specials with end dates, reviews and journal articles, so every section is filled at once. A store with its own catalogue stays exactly as it is.
The Design & layouts tab has the buttons:
Install the demo adds it on any store, next to your own products.
Remove the demo deletes exactly what the demo added and restores the settings it changed. Your own products stay.
The demo specials run for a few days after the import, so their countdowns end. To see them again, remove and add the demo, or give the products new end dates.
Set up your store in five steps
Look. On Design & layouts pick a colour scheme and a home layout, and decide whether category, product and brand pages split.
Menu. Categories with Show in top menu form the menu row and its mega panels. On Header & menu you can give a top category a short name and a featured product.
Home. On Home page add your campaign slides (a product id for the packshot and price, or your own photo), and choose the products of the tabs, The edit, the deals band and the chapters, or leave them automatic.
Promotions. Special prices with an end date (Catalog > Products > Special) get countdowns on cards, the product page and the deals band.
Product data. Duo reads your normal catalogue data:
Options named Colour or Color show as swatches; choosing one moves the image stack to the image whose file name contains that colour. Options listed under Chip option names show as chips with the price change.
Colour siblings: sell each colour as its own product and give them the same Range attribute value: they show as linked swatches.
A Ships in attribute (for example "Ships in 1-2 days") becomes delivery dates on the product page; a Video attribute adds a video button.
Manufacturers fill the brand line, the brands section and the brand pages.
Filters: add filter groups (Catalog > Filters), assign them to products and categories, and put the core Filter module in the left column of the Category layout (Design > Layouts). On split pages the filters open as a drawer.
Update
On OpenCart 4 an update is: Extensions > Extensions > Themes > Uninstall Duo, in Extensions > Installer uninstall and delete the old package, upload the new one and install it, then Install Duo again. From version 1.0.1 on, your theme settings, licence key and the demo store are kept through this, and stores that used Duo use it again.
Updating from 1.0.0: version 1.0.0 cannot keep its settings through an uninstall. Either replace the files over FTP (upload the contents of the new package's folders into extension/kv_theme_duo/, then open the Duo theme page once), which keeps everything, or note your settings and licence key before the uninstall and enter them again afterwards; then select Duo again in System > Settings.
Uninstall
Uninstalling removes Duo's events and switches a store that uses Duo back to Default. A copy of the theme settings and the demo stay (so an update keeps them). For a complete clean-up, click Remove the demo on the theme page first, then uninstall.
Configuration
Everything is on one page: Extensions > Extensions > Themes > Duo Theme by Kavio Labs > Edit (one page per store).
Design & layouts
Colour scheme: eight duotone schemes. Linen (terracotta on sand, default), Sage, Coast, Blush, Citrus, Lilac, Noir (dark, champagne on umber) and Tide (dark, aqua on petrol).
Home page: Duo, Story or Classic.
Split category, product and brand pages: on wide screens the panel shows the category, the product images or the brand. Off = these pages stay full width.
Panel caption: the chapter number and label above the slide headline.
Category pages: default view (grid or list), View switcher, Products per row (3 or 4; split pages show at most 3 next to the panel).
Your colours: action, panel, pop and paper. Leave empty to keep the scheme. A dark paper colour switches the store to dark mode.
Text logo: without a logo image the header shows the Duo mark and this text (empty = store name).
Header & menu
Three short messages in the top line (the third can link somewhere), service links, phone, sticky header, search placeholder, live search, the number of departments in the menu row, the Deals link and optional short names and featured products per department.
Home page
Each section has Show and Show on (all devices, desktop and tablet, phones). In headings, one word between two stars (for example "Shop by \category\") becomes the accent italic.
Campaign slides: label, title, text, product id or image, two buttons with links (a category id or path, p:<id>, i:<id>, specials or a URL), seconds per slide.
Service strip: four promises with icons.
Shop by category: title and category ids (empty = your top categories).
Picked for you: up to three tabs (most viewed, bestsellers, newest by default) or your product ids.
The edit: label, title, text, scene image (or the first product on the panel colour), button and three products.
Deals band: label, title, text, products (empty = specials, soonest end first); the countdown runs to the soonest special end.
Brands, Customer reviews, Journal and about (latest OpenCart 4.1 blog articles or your own stories), Newsletter card.
Store story and Department chapters (Story home): a chapter is a category with its own title, text and four products.
Category pages & cards
Subcategory chips, pagination (Show more, load while scrolling, page numbers), AJAX filters and sorting, active filter chips, brand line, quantity prices, deal countdowns, quick view, compare, discount and New flags, low stock line.
Product pages
Hover zoom, sticky add-to-cart bar, structured data, perks under the buy button, related products title, video attribute, colour and chip option names, range, colour and delivery attributes.
Footer & mobile
Payment chips (plain text), social links (one "Name|URL" per line), mobile bottom bar, back to top button.
Licence
Enter the licence key from your Kavio Labs account. The theme never blocks the storefront or the admin: without a valid key it keeps working and the theme page shows a reminder. New installs run a 14-day trial; a licence includes 12 months of updates and support.
FAQ
Does Duo change OpenCart core files or use OCMOD?
No. Duo is an OpenCart 4 theme extension that works with events only. Uninstall it or switch the store theme back to Default and the stock look returns.
What happens on phones?
Phones get one column: the campaign slides become a block at the top of the home page, category pages show the category head with subcategory chips, product pages show the swipe gallery. The split starts at 1024 px.
Can I turn the split off?
Yes. Choose the Classic home layout and switch off "Split category, product and brand pages".
My product images look small or cropped. Use square packshots (600 x 600 for cards, 1000 x 1000 for the product page) on a white or transparent background. Duo shows them on a light plate in every scheme.
Does Duo work with other extensions?
Duo keeps OpenCart's own markup for cart, checkout, account and the layout positions, and restyles the pages it does not template. Extensions that add to pages through events or layout modules keep working.
Is there an OpenCart 3 version?
No. Duo needs OpenCart 4.1.0.0 or later (Bootstrap 5).
Is Duo the same as Duo for CS-Cart?
It is the same design and demo store, built for OpenCart. The two are separate products.
Do I lose my settings when I update?
No, from version 1.0.1 on. An OpenCart 4 update is uninstall + install; Duo keeps a copy of its settings and licence key and puts them back when it is installed again, and the demo store stays. Updating from 1.0.0: see Installation > Update.
Server-side tracking for OpenCart 4.x and 3.0.x: purchases, refunds, add to cart, checkout, product views and leads go from your server to the free official GA4 Measurement Protocol, Meta Conversions API and TikTok Events API, deduplicated with the browser pixels through shared event ids. Consent-aware, SHA-256 hashed customer data, order status mapping, queue with retries, test mode and an event log. No paid relay, events only, no OCMOD.
The department store theme for OpenCart 4.x and 3.0.x: colour-coded departments, a department list beside the hero slider with two side promos, a big search with a department selector, tabbed product blocks, a 2 + 1 + 2 offer grid, deals of the day with real countdowns, a department showcase, a promotions band and a three-column product page with a sticky buy box. Four styles (Meridian, Harbor, Citrus, Night) and your own colours on top. Events only, no core changes.
Stop AI crawlers, scrapers, vulnerability scanners and unwanted countries before OpenCart 4.x or 3.0.x builds a page. Googlebot and Bingbot are verified by DNS and always allowed; 50+ bots get one switch each; country rules use free GeoIP databases and can close only the checkout; IP and network lists, rate limits, honeypots and the cart flood fix; a one-second challenge instead of a captcha; learning mode, dashboard, log, IP tester and Cloudflare export. No core changes, no OCMOD.
