Apple Mail iOS email CSS: what breaks, and what to write instead

275 of 300 features work in Apple Mail iOS · 12 partial · 11 not supported · 2 untested. Of the 275 that work here, 84 work in 6 or fewer of the other 20 clients, so a check that passes here says little about the rest.

Works 275 · Partial 12 · Not supported 11 · Untested 2 · of 300

WebKit · mobile · prefers-color-scheme: works

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No signup · Five clients free, Outlook Classic included · All 21 with an account

The checker needs a computer screen.

See what breaks ↓

Apple Mail iOS is one of the five clients the checker runs with no account.

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@emailens/engine 0.18.22 · data last changed 10 Nov 2026

What works in Apple Mail iOS and breaks elsewhere

84 features work in Apple Mail iOS and in 6 or fewer of the other 20 clients, so they need a fallback.

All 80

Not listed: <link>, <base>, @import, <body>, structural tags; the table below has them.

Apple Mail iOS on real installs

The Emailens probe for each feature, captured on Apple Mail iOS's own installs, next to the Emailens live preview of Apple Mail iOS.

animation in a real Apple Mail (iPhone 13)

The Emailens probe for animation on a real Apple Mail (iPhone 13) — Apple Mail iOS

The same probe in the Emailens live preview of Apple Mail iOS — Apple Mail iOS

overflow in a real Apple Mail (iPhone 13)

The Emailens probe for overflow on a real Apple Mail (iPhone 13) — Apple Mail iOS

word-break in a real Apple Mail (iPhone 13)

The Emailens probe for word-break on a real Apple Mail (iPhone 13) — Apple Mail iOS

Paste your email and see what Apple Mail iOS does to it.

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No signup · Five clients free, Outlook Classic included · All 21 with an account

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Dark mode in Apple Mail iOS

Works @media prefers-color-scheme works in Apple Mail iOS.

Works in 9 of 21.
Works color-scheme works in Apple Mail iOS.

Works in 4 of 21.
Not supported meta-color-scheme is not supported in Apple Mail iOS.

Works in 2 of 21.

Live preview: Apple Mail supports @media (prefers-color-scheme: dark). Without it, email content renders unchanged in dark mode.

How to target Apple Mail iOS

Selectors that single out Apple Mail iOS, from the community list the engine ships (howtotarget.email). Copy one and replace .your-class-name.

css

5 lines

@supports (-webkit-overflow-scrolling:touch) and (color:#ffff) {
  .your-class-name {
    /* Replace this comment with your styles */
  }
}

css

3 lines

[class^="apple-mail"] .your-class-name {
  /* Replace this comment with your styles */
}

Targets both iOS and MacOS Applemail.

css

3 lines

.Singleton .your-class-name {
  /* Replace this comment with your styles */
}

Build one for several clients →

Before you send to Apple Mail iOS

Test with the device set to maximum Dynamic Type to surface auto-scaled typography that breaks layout.
Check tap-target sizes, Apple's HIG recommends 44pt minimum, which translates to roughly 44px buttons in email.

Every account includes one free real-device check in classic Outlook, Outlook for Mac and Apple Mail, after you verify your email and run one preview, while this month's free capacity lasts. How real-device checks work →

Your next question

Apple Mail

Every feature in Apple Mail iOS

What breaks here (23) Everything (300) Untested (2)

HTML Elements · 2 of 48 not supported or partial here

<abbr> Works Works in 14 of 21
<acronym> Works Works in 13 of 21
<address> Works Works in 20 of 21
<audio> Works Works in 4 of 21
<base> Works Works in 4 of 21
<bdi> Works Works in 6 of 21
<blockquote> Works Works in 19 of 21
<body> Works Works in 5 of 21
<button type="reset"> Works Works in 10 of 21
<button type="submit"> Works Works in 11 of 21
<code> Works Works in 20 of 21
<del> Works Works in 20 of 21
<dfn> Works Works in 17 of 21
<dialog> Works Works in 5 of 21
<div> Works Works in 20 of 21
<form> Works Works in 10 of 21
<h1> Works Works in 20 of 21
<hr> Works Works in 18 of 21
<img> Works Works in 19 of 21
<input type="checkbox"> Works Works in 16 of 21
<input type="hidden"> Works Works in 16 of 21
<input type="radio"> Works Works in 16 of 21
<input type="reset"> Works Works in 15 of 21
<input type="submit"> Works Works in 12 of 21
<input type="text"> Works Works in 13 of 21
<link> Works Works in 3 of 21
<marquee> Works Works in 8 of 21
<meter> Works Works in 11 of 21
<object> Works Works in 1 of 21
<p> Works Works in 20 of 21
<picture> Works Works in 4 of 21
<pre> Works Works in 20 of 21
<progress> Works Works in 6 of 21
<rp> Works Works in 15 of 21
<rt> Works Works in 15 of 21
<ruby> Works Works in 15 of 21
<select> Buggy. Partial Works in 14 of 21
<small> Works Works in 20 of 21
<span> Works Works in 20 of 21
<strike> Works Works in 17 of 21
<strong> Works Works in 20 of 21
<style> Works Works in 16 of 21
<svg> Works Works in 5 of 21
<table> Works Works in 20 of 21
<textarea> Works Works in 13 of 21
<ul> Works Works in 7 of 21
<video> Partial support. Partial Works in 3 of 21
<wbr> Works Works in 16 of 21

HTML Attributes · 1 of 22 not supported or partial here

[align] Works Works in 17 of 21
[aria-describedby] Works Works in 9 of 21
[aria-hidden] Works Works in 13 of 21
[aria-label] Works Works in 13 of 21
[aria-labelledby] Works Works in 7 of 21
[aria-live] Works Works in 8 of 21
[background] Works Works in 16 of 21
[cellpadding] Works Works in 18 of 21
[cellspacing] Works Works in 18 of 21
[command] Works Works in 3 of 21
[dir] Works Works in 19 of 21
[height] Works Works in 18 of 21
[hidden] Works Works in 5 of 21
[lang] Works Works in 15 of 21
[loading] Works Works in 4 of 21
[popover] Works Works in 3 of 21
[required] Works Works in 7 of 21
[role] Works Works in 14 of 21
[srcset] Works Works in 4 of 21
[target] The attribute is supported but links always open in a new window anyway. Partial Works in 0 of 21
[valign] Works Works in 20 of 21
[width] Works Works in 18 of 21

HTML & Email Structure · 2 of 8 not supported or partial here

amp4email Not supported Works in 6 of 21
anchor-links Works Works in 12 of 21
doctype Works Works in 13 of 21
html-comments Works Works in 18 of 21
html5-semantics Works Works in 6 of 21
image-maps Works Works in 15 of 21
mailto-links Works Works in 17 of 21
meta-color-scheme Not supported Works in 2 of 21

CSS At-Rules · 1 of 10 not supported or partial here

@font-face Works Works in 6 of 21
@import Works Works in 4 of 21
@keyframes Works Works in 7 of 21
@media Works Works in 5 of 21
@media device-pixel-ratio Works Works in 10 of 21
@media hover Works Works in 9 of 21
@media orientation Partial. Partial Works in 11 of 21
@media prefers-color-scheme Works Works in 9 of 21
@media prefers-reduced-motion Works Works in 9 of 21
@supports Works Works in 9 of 21

Pseudo-Elements · 0 of 6 not supported or partial here

::after Works Works in 6 of 21
::before Works Works in 6 of 21
::first-letter Works Works in 10 of 21
::first-line Works Works in 10 of 21
::marker Works Works in 10 of 21
::placeholder Works Works in 9 of 21

Pseudo-Classes & Selectors · 4 of 34 not supported or partial here

:adjacent-sibling Works Works in 16 of 21
:attribute-selector Works Works in 6 of 21
:chaining Works Works in 14 of 21
:checked Works Works in 9 of 21
:child-combinator Works Works in 16 of 21
:class-selector Works Works in 17 of 21
:descendant-combinator Works Works in 17 of 21
:first-child Works Works in 12 of 21
:first-of-type Works Works in 12 of 21
:focus Not supported Works in 10 of 21
:focus-visible Untested Works in 6 of 21
:focus-within Untested Works in 6 of 21
:general-sibling Works Works in 16 of 21
:grouping Works Works in 17 of 21
:has Works Works in 5 of 21
:hover Works Works in 12 of 21
:id-selector Works Works in 17 of 21
:lang Works Works in 6 of 21
:last-child Works Works in 12 of 21
:last-of-type Works Works in 12 of 21
:link Works Works in 13 of 21
:not Works Works in 6 of 21
:nth-child Works Works in 6 of 21
:nth-last-child Works Works in 6 of 21
:nth-of-type Works Works in 6 of 21
:only-child Works Works in 12 of 21
:only-of-type Works Works in 12 of 21
:target Not supported Works in 7 of 21
:type-selector Works Works in 17 of 21
:universal-selector Works Works in 16 of 21
:visited Not supported Works in 8 of 21
pseudo-class-active Not supported Works in 8 of 21
pseudo-class-default Works Works in 10 of 21
pseudo-class-nth-last-of-type Works Works in 6 of 21

CSS Functions · 0 of 8 not supported or partial here

calc Works Works in 8 of 21
clamp Works Works in 6 of 21
conic-gradient Works Works in 6 of 21
fit-content Works Works in 11 of 21
linear-gradient Works Works in 9 of 21
max Works Works in 6 of 21
min Works Works in 6 of 21
radial-gradient Works Works in 10 of 21

CSS Properties · 13 of 164 not supported or partial here

!important Works Works in 11 of 21
accent-color Works Works in 5 of 21
align-items Works Works in 13 of 21
animation Works Works in 5 of 21
aspect-ratio Works Works in 5 of 21
backdrop-filter Works Works in 6 of 21
background Works Works in 16 of 21
background-blend-mode Works Works in 13 of 21
background-clip Works Works in 14 of 21
background-color Works Works in 21 of 21
background-image Works Works in 16 of 21
background-origin Works Works in 14 of 21
background-position Works Works in 20 of 21
background-repeat Works Works in 20 of 21
background-size Works Works in 17 of 21
bimi Works Works in 9 of 21
block-size Works Works in 7 of 21
border Works Works in 20 of 21
border-collapse Works Works in 19 of 21
border-image Works Works in 7 of 21
border-inline Works Works in 3 of 21
border-inline-individual Works Works in 3 of 21
border-inline-longhand Works Works in 4 of 21
border-radius Works Works in 16 of 21
border-radius-logical Works Works in 3 of 21
border-spacing Works Works in 17 of 21
bottom Works Works in 11 of 21
box-shadow Works Works in 14 of 21
box-sizing Works Works in 16 of 21
caption-side Works Works in 20 of 21
clear Works Works in 9 of 21
clip-path Works Works in 8 of 21
color Works Works in 21 of 21
color-scheme Works Works in 4 of 21
column-count Works Works in 16 of 21
columns Works Works in 16 of 21
css-comments Works Works in 14 of 21
cursor iOS assistive touch does not respond to cursor. Not supported Works in 2 of 21
custom-properties Works Works in 6 of 21
direction Works Works in 21 of 21
display Works Works in 13 of 21
display:flex Works Works in 18 of 21
display:grid Works Works in 18 of 21
display:none Works Works in 20 of 21
empty-cells Works Works in 14 of 21
filter Works Works in 7 of 21
flex Works Works in 13 of 21
flex-basis Works Works in 13 of 21
flex-direction Works Works in 12 of 21
flex-wrap Works Works in 13 of 21
float Works Works in 14 of 21
font Works Works in 20 of 21
font-family Works Works in 21 of 21
font-kerning Works Works in 13 of 21
font-size Works Works in 13 of 21
font-size-adjust Works Works in 10 of 21
font-stretch Works Works in 10 of 21
font-weight Works Works in 16 of 21
gap Works Works in 7 of 21
grid-template-columns Works Works in 7 of 21
height Works Works in 16 of 21
hyphenate-character Works Works in 4 of 21
hyphenate-limit-chars Not supported Works in 1 of 21
hyphens Works Works in 4 of 21
inert Works Works in 3 of 21
inline-size Not supported Works in 4 of 21
inset Works Works in 3 of 21
justify-content Works Works in 13 of 21
left Works Works in 11 of 21
letter-spacing Works Works in 20 of 21
light-dark Works Works in 3 of 21
line-height Works Works in 20 of 21
list-style Works Works in 11 of 21
list-style-image Works Works in 6 of 21
list-style-position Works Works in 19 of 21
list-style-type Works Works in 21 of 21
margin Works Works in 8 of 21
margin-block-start-end Works Works in 4 of 21
margin-inline-block Works Works in 6 of 21
margin-inline-start-end Works Works in 4 of 21
mask-image Works Works in 4 of 21
max-block-size Works Works in 5 of 21
max-height Works Works in 20 of 21
max-inline-size Works Works in 4 of 21
max-width Works Works in 20 of 21
min-block-size Works Works in 4 of 21
min-height Works Works in 19 of 21
min-inline-size Works Works in 5 of 21
min-width Works Works in 20 of 21
mix-blend-mode Works Works in 13 of 21
modern-color Works Works in 4 of 21
nesting Works Works in 2 of 21
object-fit Works Works in 14 of 21
object-position Works Works in 14 of 21
opacity Works Works in 19 of 21
orphans Works Works in 10 of 21
outline Works Works in 20 of 21
outline-offset Works Works in 7 of 21
overflow Partial. Partial Works in 4 of 21
overflow-wrap Buggy. Partial Works in 2 of 21
padding Works Works in 20 of 21
padding-block-start-end Works Works in 4 of 21
padding-inline-block Works Works in 3 of 21
padding-inline-start-end Works Works in 4 of 21
position Partial. Partial Works in 2 of 21
resize Not supported Works in 1 of 21
rgb Works Works in 12 of 21
rgba Works Works in 12 of 21
right Works Works in 11 of 21
scroll-snap Works Works in 6 of 21
shape-margin Works Works in 6 of 21
shape-outside Works Works in 6 of 21
system-ui Works Works in 12 of 21
tab-size Works Works in 8 of 21
table-layout Works Works in 16 of 21
text-align Works Works in 13 of 21
text-align-last Works Works in 7 of 21
text-decoration Observed 2026-10-14 (Emailens real-device probe, Apple Mail (iPhone 13)): The multi-value shorthand text-decoration: underline wavy #d33 was dropped whole: no line at all. Partial Works in 14 of 21
text-decoration-color Works Works in 17 of 21
text-decoration-line Works Works in 16 of 21
text-decoration-skip-ink Works Works in 7 of 21
text-decoration-style Works Works in 16 of 21
text-decoration-thickness Works Works in 7 of 21
text-emphasis Works Works in 9 of 21
text-emphasis-position Works Works in 4 of 21
text-indent Works Works in 13 of 21
text-justify Buggy. Not supported Works in 0 of 21
text-orientation Works Works in 13 of 21
text-overflow Works Works in 13 of 21
text-shadow Works Works in 12 of 21
text-transform Works Works in 20 of 21
text-underline-offset Works Works in 7 of 21
text-underline-position Partial. Partial Works in 8 of 21
text-wrap Works Works in 4 of 21
top Works Works in 11 of 21
transform Works Works in 7 of 21
transition Works Works in 4 of 21
unit-ch Works Works in 15 of 21
unit-cm Works Works in 20 of 21
unit-em Works Works in 20 of 21
unit-ex Works Works in 20 of 21
unit-in Works Works in 20 of 21
unit-initial Works Works in 12 of 21
unit-mm Works Works in 20 of 21
unit-pc Works Works in 20 of 21
unit-percent Works Works in 20 of 21
unit-pt Works Works in 20 of 21
unit-px Works Works in 20 of 21
unit-rem Works Works in 15 of 21
unit-vh Buggy. Partial Works in 17 of 21
unit-vmax Works Works in 15 of 21
unit-vmin Works Works in 15 of 21
unit-vw Works Works in 18 of 21
user-select Works with -webkit prefix Partial Works in 3 of 21
vertical-align Works Works in 21 of 21
visibility Works Works in 13 of 21
white-space Works Works in 15 of 21
white-space-collapse Works Works in 4 of 21
widows Works Works in 10 of 21
width Works Works in 20 of 21
word-break Buggy. Partial Works in 4 of 21
word-spacing Works Works in 14 of 21
writing-mode Works Works in 13 of 21
z-index Works Works in 17 of 21

How Apple Mail iOS renders email

Apple Mail on iOS uses the same WebKit engine as the macOS version, providing excellent CSS support. It handles responsive design well, supports media queries, and renders most modern CSS without issues. However, the mobile viewport introduces its own considerations for touch targets and readability.

Auto-linking phone numbers and dates: iOS automatically converts phone numbers, dates, and addresses into tappable links, adding its own blue styling. Use meta tag <meta name="format-detection" content="telephone=no"> to prevent this, or style the auto-generated links explicitly.
Minimum font size: iOS may scale up fonts smaller than 13px to improve readability. Use -webkit-text-size-adjust: 100% to prevent automatic scaling.

Apple Mail iOS shares the macOS rendering pipeline, so feature support is nearly identical. The differences are mostly viewport-related, narrower screens, no hover surface, and touch-target sizing requirements.
Dynamic Type and Apple's accessibility text-size settings can override declared font-size on body copy. Use -webkit-text-size-adjust: 100% on critical typography to opt out.
Auto-linking is aggressive, phone numbers, dates, addresses, and tracking numbers are all converted to tappable spans with blue underline. Wrap any non-link text that resembles these patterns in explicit anchor tags with overrides.
Safe areas and the notch on iPhone X+ devices can clip full-bleed designs. Reserve at least 16px horizontal padding on the outer container.