iOS 27.3 Safari: Vertical Tabs and Adaptive Dark Mode
Apple’s iOS 27.3, iPadOS 27.3 and macOS 27.3 developer betas add two notable Safari changes: Vertical Tabs and Adaptive Dark Mode. Vertical Tabs move open pages into a side-by-side list, while Adaptive Dark Mode can turn a bright website into a darker version when the site does not provide its own dark theme. This guide explains where to enable both features, which devices need Apple Intelligence, and why the dark-mode preview may not appear.
Quick answer: How do you enable Safari Vertical Tabs?
On iPhone: Open Settings → Apps → Safari, then find the new Vertical Tabs option. On iPad and Mac: Open Safari and use the View menu to select Vertical Tabs. The feature is part of Safari 27.3 beta and does not require Apple Intelligence. Setup details from 9to5Mac.
Check which iOS 27.3 Safari features your device can use
Use this quick guide to separate the standard Safari changes from the Siri actions that need Apple Intelligence. It is based on Developer Beta 1 reporting and does not replace Apple’s final compatibility list.
The checker reports the published beta findings as of November 5, 2026. Apple can change eligibility or menu labels before the stable release.
How to turn on Vertical Tabs in Safari
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Vertical Tabs place open tabs in a column on the left side rather than keeping every tab in a horizontal strip. They can show compact website icons or be widened to reveal page titles. MacRumors reports that the layout continues to work with Tab Groups and pinned tabs. MacRumors’ beta walkthrough.
On iPhone
- Install the iOS 27.3 beta on a compatible test device.
- Open the iPhone’s Settings app.
- Tap Apps, then Safari.
- Find the new Vertical Tabs option and select it.
- Open Safari and check the tab sidebar. If the labels are too narrow, widen the sidebar where the beta interface allows it.
On iPad and Mac
- Make sure the device is running the relevant 27.3 beta.
- Open Safari.
- Open the View menu and choose the Vertical Tabs layout, where available.
- Resize the sidebar to show more of each website title.
Does it need Apple Intelligence? No. The vertical tab layout is separate from Siri’s AI-powered tab-management actions. Do not confuse the optional AI features with the basic Safari layout change.
How Safari Adaptive Dark Mode works
Adaptive Dark Mode is designed for websites that remain bright even when your device is using Dark Mode. WebKit says Safari analyses a page’s appearance and transforms colours to create a darker presentation while trying to preserve readability. It can adjust backgrounds, text contrast, graphics, vector artwork, surfaces and shadows. Read the official WebKit explanation.
It is not a simple full-page colour inversion. WebKit describes a colour transformation that aims to preserve hue and maintain readable text contrast, including a target of 4.5:1 for transformed text. Most photos are left unchanged; some SVG artwork and simple black-and-white logos may be adjusted. Canvas content is left unchanged because it can contain many different kinds of graphics. The result can therefore vary from one website to another.
How to try Adaptive Dark Mode
- Set your iPhone, iPad or Mac appearance to Dark.
- Open a website with a predominantly bright background in Safari 27.3 beta.
- When Safari offers the Adaptive Dark Mode preview, tap Try.
- After previewing it, choose whether to keep the adaptation for that website or use it more broadly, where the beta offers that choice.
Adaptive Dark Mode Preview Lab
Try a visual example of how a bright web page can look in a dark presentation.
Why does this page look bright?
This sample represents a site that has a light appearance and no native dark theme. Safari’s actual transformation is performed by WebKit and may look different from this illustrative preview.
Reading guideUpdated todayPage settings
Good contrast, readable text and preserved image colours help a page remain usable after a theme transformation.
This is an original UIG CSS illustration, not a browser emulator and not a pixel-accurate reproduction of Safari’s WebKit processing.
Why might the Adaptive Dark Mode prompt not appear?
| What you see | Likely reason | What to check |
|---|---|---|
| No preview prompt on any site | System appearance may still be Light, or the device may not be running Safari 27.3 beta. | Switch system appearance to Dark and confirm the Safari version. |
| One website stays in its own dark theme | The website already provides a native dark colour scheme. | This is expected; WebKit says sites declaring light and dark scheme support are not transformed. |
| A bright site still looks unchanged | The site may not meet the beta’s criteria, or the prompt may not have been accepted. | Try another predominantly light page and look for the Safari preview. |
| Some graphics look different | Adaptive Dark Mode selectively adjusts some colours and artwork, but not every element can be transformed identically. | Compare the page with its original appearance and report beta problems through Feedback Assistant. |
Does Adaptive Dark Mode require Apple Intelligence?
No, not for the Safari visual transformation. WebKit describes Adaptive Dark Mode as a Safari 27.3 beta browser feature that responds to system appearance and website colours. The separate Siri AI actions are the features that require an Apple Intelligence-capable device. WebKit’s technical explanation · MacRumors’ feature report.
| Feature | Platforms reported | Apple Intelligence needed? | Important condition |
|---|---|---|---|
| Vertical Tabs | iPhone, iPad and Mac with Safari 27.3 beta | No | Menu and layout controls differ by platform. |
| Adaptive Dark Mode | iPhone, iPad and Mac with Safari 27.3 beta | No | System Dark Mode must be enabled; sites with a native dark scheme are not transformed. |
| Siri AI Safari actions | Supported Apple Intelligence devices | Yes | Availability also depends on supported language, region, software and the beta feature rollout. |
| Expanded StandBy faces | iPhone 11 and newer, according to beta reporting | No | StandBy uses landscape orientation while charging. Always-On display behaviour depends on iPhone hardware. |
What else changes in iOS 27.3 StandBy?
Alongside the Safari changes, the beta expands several StandBy customisation options beyond the iPhone Duo. MacRumors reports that the updated clock faces, Shared Album Photos face, new Calendar and Weather faces, and multiple saved versions of faces are coming to iPhone 11 and newer models compatible with the update. Read the StandBy feature report.
StandBy itself is designed to display information when an iPhone is positioned in landscape on a charger. Do not assume that every iPhone supporting the new faces also has an Always-On display; that remains dependent on the model’s display hardware.
For website developers: how to avoid unwanted colour changes
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WebKit recommends declaring the colour schemes a website genuinely supports. A site that supports both light and dark themes can declare that support in its document head:
<meta name="color-scheme" content="light dark">It can also declare the supported schemes in CSS:
:root {
color-scheme: light dark;
}WebKit says Adaptive Dark Mode does not transform pages that already signal support for both light and dark colour schemes. It also documents a light only opt-out, but explicitly warns that the only keyword is not supported in Safari 27.3 beta 1. Do not tell readers that this opt-out reliably works in the current first beta. Recheck the behaviour in later betas. WebKit: Making your site work even better.
A privacy detail: websites cannot detect the transformation
WebKit says Safari does not expose whether Adaptive Dark Mode has been applied. A website script that reads CSS colours receives the original authored values, not the transformed colours. This limits the extra fingerprinting signal that would be created if sites could identify which visitors had enabled the feature. WebKit privacy explanation.
Frequently asked questions
Where is Vertical Tabs in iOS 27.3 Safari?
On iPhone, open Settings, tap Apps, choose Safari, then look for Vertical Tabs. On iPad and Mac, the option is also available through Safari’s View menu in the beta.
Does Safari Adaptive Dark Mode work without Apple Intelligence?
Yes. The visual page transformation is separate from Apple Intelligence. The system appearance must be Dark, and Safari must detect a bright page without a native dark theme.
Why does Adaptive Dark Mode not appear on some websites?
A website that already declares and supports a dark colour scheme may be left unchanged. The prompt also depends on system Dark Mode and the beta’s page detection.
Which iPhones get the expanded StandBy faces?
MacRumors reports that iPhone 11 and newer models compatible with iOS 27.3 receive the expanded StandBy face options. Always-On display behaviour still depends on the specific iPhone model.
Can a website block Safari Adaptive Dark Mode?
WebKit documents colour-scheme declarations for sites that provide their own appearance. It also documents a light-only opt-out, but says the only keyword is not supported in Safari 27.3 beta 1. Site owners should test later beta releases before relying on it.
Is iOS 27.3 available to everyone?
As of November 5, 2026, Apple has announced the developer beta. The public release is expected in December according to reporting about Apple’s release timing. Wait for a public or stable release if you do not want beta software.
Ultimate Info Guide is an independent publication and is not affiliated with or endorsed by Apple Inc. Feature descriptions are based on developer beta information checked on November 5, 2026. Menu names and availability can change before the public release.
