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Apple Mail

Engine: WebKit·desktop·Dark mode: Yes

Apple Mail on macOS uses the WebKit rendering engine — the same engine that powers Safari. This gives it excellent CSS support, including flexbox, grid, animations, and custom fonts. It's one of the most capable email clients for modern CSS.

The default email client on macOS. Popular among developers, designers, and creative professionals. High market share in North America and Europe.

CSS coverage profile for Apple Mail

Apple Mail renders with the WebKit engine and supports 234 of 251 tracked CSS and HTML features fully, with 12 partially supported and 5 unsupported. That places it in a broad coverage band.

Modern CSS works largely as expected. The cost of supporting this client is low — most production templates need only minor adjustments.

234

Supported

12

Partial

5

Unsupported

251

Total

Key gotchas in Apple Mail

CSS specificity in dark mode

Apple Mail's dark mode can override your explicit colors if specificity isn't high enough. Use !important on critical color declarations in your dark mode media query.

Video/audio autoplay

Apple Mail supports <video> and <audio> but autoplay behavior varies by macOS version. Don't rely on media playback for critical content.

Interactive elements

While Apple Mail renders forms and interactive CSS, emails are a read-only context. Interactive features won't persist or submit data.

How Apple Mail renders email

  • Apple Mail macOS renders email through WebKit, so behaviour aligns closely with Safari. Modern CSS — flexbox, grid, custom properties, animations, transitions — works as expected.
  • Mail's dark mode is deeply integrated with macOS's appearance setting. The client respects color-scheme meta tags, prefers-color-scheme media queries, and applies its own intelligent inversion as a fallback.
  • Custom fonts load reliably from any CORS-permitted host. @font-face declarations in <style> blocks are preserved.
  • Apple Mail enforces Privacy Protection (since macOS 12), which proxies image fetches, masking IP addresses and frustrating granular open-rate analytics.

Dark mode behaviour in Apple Mail

Apple Mail has the most sophisticated dark mode handling of any email client. It respects color-scheme meta tags, supports prefers-color-scheme media queries, and applies intelligent color inversion for emails that don't declare explicit dark mode styles.

QA checklist for Apple Mail

  • Test rendering in both light and dark macOS appearances — Mail's automatic inversion can produce surprising results on emails that don't declare dark-mode styles.
  • Verify image rendering accounts for Mail Privacy Protection — load times can shift visibly when images are proxied.
  • Check that explicit color values survive the dark-mode pass; pair color and background-color on every text-bearing element.

Related clients

HTML Elements40

FeatureSupport
<abbr>Supported
<acronym>Supported
<address>Supported
<audio>Supported
<base>Supported
<bdi>Supported
<blockquote>Supported
<body>Supported
<code>Supported
<del>Supported
<dfn>Supported
<dialog>Supported
<div>Supported
<form>Supported
<h1>Supported
<hr>Supported
<img>Supported
<link>Supported
<marquee>Supported
<meter>Supported
<object>Partial
<p>Supported
<picture>Partial
<pre>Supported
<progress>Supported
<rp>Supported
<rt>Supported
<ruby>Supported
<select>Supported
<small>Supported
<span>Supported
<strike>Supported
<strong>Supported
<style>Supported
<svg>Partial
<table>Supported
<textarea>Supported
<ul>Supported
<video>Supported
<wbr>Supported

CSS At-Rules5

FeatureSupport
@font-faceSupported
@importSupported
@keyframesSupported
@mediaSupported
@supportsSupported

Pseudo-Elements6

FeatureSupport
::afterSupported
::beforeSupported
::first-letterSupported
::first-lineSupported
::markerSupported
::placeholderSupported

Pseudo-Classes & Selectors32

FeatureSupport
:adjacent-siblingSupported
:attribute-selectorSupported
:chainingSupported
:checkedSupported
:child-combinatorSupported
:class-selectorSupported
:descendant-combinatorSupported
:first-childSupported
:first-of-typeSupported
:focusSupported
:general-siblingSupported
:groupingSupported
:hasSupported
:hoverSupported
:id-selectorSupported
:langSupported
:last-childSupported
:last-of-typeSupported
:linkSupported
:notSupported
:nth-childSupported
:nth-last-childSupported
:nth-of-typeSupported
:only-childSupported
:only-of-typeSupported
:targetUnsupported
:type-selectorSupported
:universal-selectorSupported
:visitedUnsupported
pseudo-class-activePartial
pseudo-class-defaultSupported
pseudo-class-nth-last-of-typeSupported

CSS Functions8

FeatureSupport
calcSupported
clampSupported
conic-gradientSupported
fit-contentSupported
linear-gradientSupported
maxSupported
minSupported
radial-gradientSupported

CSS Properties160

FeatureSupport
!importantSupported
accent-colorSupported
align-itemsSupported
animationSupported
aspect-ratioSupported
backdrop-filterSupported
backgroundSupported
background-blend-modeSupported
background-clipSupported
background-colorSupported
background-imageSupported
background-originSupported
background-positionSupported
background-repeatSupported
background-sizeSupported
bimiSupported
block-sizeSupported
borderSupported
border-collapseSupported
border-imageSupported
border-inlineSupported
border-inline-individualSupported
border-inline-longhandSupported
border-radiusSupported
border-radius-logicalSupported
border-spacingSupported
bottomSupported
box-shadowSupported
box-sizingSupported
caption-sideSupported
clearSupported
clip-pathSupported
colorSupported
color-schemeSupported
column-countSupported
columnsSupported
css-commentsSupported
cursorPartial
custom-propertiesSupported
directionSupported
displaySupported
display:flexSupported
display:gridSupported
display:noneSupported
empty-cellsSupported
filterSupported
flex-directionSupported
flex-wrapSupported
floatSupported
fontSupported
font-familySupported
font-kerningSupported
font-sizeSupported
font-stretchSupported
font-weightSupported
gapSupported
grid-template-columnsSupported
heightSupported
hyphenate-characterSupported
hyphenate-limit-charsUnsupported
hyphensSupported
inline-sizeUnsupported
insetSupported
justify-contentSupported
leftSupported
letter-spacingSupported
light-darkSupported
line-heightSupported
list-styleSupported
list-style-imageSupported
list-style-positionSupported
list-style-typeSupported
marginSupported
margin-block-start-endSupported
margin-inline-blockSupported
margin-inline-start-endSupported
mask-imageSupported
max-block-sizeSupported
max-heightSupported
max-inline-sizeSupported
max-widthSupported
min-block-sizeSupported
min-heightSupported
min-inline-sizeSupported
min-widthSupported
mix-blend-modeSupported
modern-colorSupported
nestingPartial
object-fitSupported
object-positionSupported
opacitySupported
orphansSupported
outlineSupported
outline-offsetSupported
overflowPartial
overflow-wrapPartial
paddingSupported
padding-block-start-endSupported
padding-inline-blockSupported
padding-inline-start-endSupported
positionPartial
resizePartial
rgbSupported
rgbaSupported
rightSupported
scroll-snapSupported
shape-marginSupported
shape-outsideSupported
system-uiSupported
tab-sizeSupported
table-layoutSupported
text-alignSupported
text-align-lastSupported
text-decorationSupported
text-decoration-colorSupported
text-decoration-lineSupported
text-decoration-skip-inkSupported
text-decoration-styleSupported
text-decoration-thicknessSupported
text-emphasisSupported
text-emphasis-positionSupported
text-indentSupported
text-justifyUnsupported
text-orientationSupported
text-overflowSupported
text-shadowSupported
text-transformSupported
text-underline-offsetSupported
text-underline-positionPartial
text-wrapSupported
topSupported
transformSupported
transitionSupported
unit-chSupported
unit-cmSupported
unit-emSupported
unit-exSupported
unit-inSupported
unit-initialSupported
unit-mmSupported
unit-pcSupported
unit-percentSupported
unit-ptSupported
unit-pxSupported
unit-remSupported
unit-vhSupported
unit-vmaxSupported
unit-vminSupported
unit-vwSupported
user-selectSupported
vertical-alignSupported
visibilitySupported
white-spaceSupported
white-space-collapseSupported
widowsSupported
widthSupported
word-breakPartial
word-spacingSupported
writing-modeSupported
z-indexSupported

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Support data last updated Apr 27, 2026 · synced from caniemail.com via @emailens/engine.