Outlook
Outlook includes Microsoft Outlook desktop clients and Outlook web versions. Limited CSS support compared to modern web email.
About Outlook
Outlook includes multiple clients: desktop applications (2007–2019), Outlook.com webmail, and mobile versions. Desktop Outlook has notoriously limited CSS support due to its rendering engine. This makes Outlook one of the most challenging email clients to design for.
CSS & Design Tips
- Outlook desktop often ignores CSS and falls back to HTML tables for layout
- Use VML (Vector Markup Language) for background images in desktop Outlook
- Mobile Outlook and Outlook.com have better CSS support than desktop versions
- Conditional comments (for Outlook) are no longer supported in modern versions
- Test across all Outlook versions (2007–2019, Outlook.com, and mobile) as support varies significantly
Best Practices
When designing for Outlook, always test your emails across all major versions. CSS support can vary dramatically between desktop and web versions. Use VML for advanced styling and provide HTML table fallbacks.
Supported Features
align-items
css
animation
css
@font-face
css
@import
css
@keyframes
css
@media (-webkit-device-pixel-ratio)
css
@media (hover), @media (any-hover)
css
@media (orientation)
css
@media (prefers-color-scheme)
css
@media (prefers-reduced-motion)
css
@media
css
@supports
css
backdrop-filter
css
background-blend-mode
css
background-clip
css
background-color
css
background-image
css
background-origin
css
background-position
css
background-repeat
css
background-size
css
background
css
block-size & inline-size
css
border-collapse
css
border-image
css
border-inline & border-block longhand properties
css
border-radius
css
border-spacing
css
border
css
box-shadow
css
box-sizing
css
caption-side
css
clear
css
clip-path
css
column-count
css
css column properties
css
CSS comments
css
conic-gradient()
css
direction
css
display:flex
css
display:grid
css
display:none
css
display
css
empty-cells
css
filter
css
flex-direction:column
css
flex-wrap: wrap
css
float
css
font-kerning
css
font-size
css
font-stretch
css
font-weight
css
font shorthand
css
max()
css
min()
css
gap, column-gap, row-gap
css
grid-template-* properties
css
height property
css
hyphens
css
!important keyword
css
fit-content, min-content, max-content
css
justify-content
css
left, right, top, bottom
css
letter-spacing
css
line-height
css
linear-gradient()
css
list-style-image
css
list-style-position
css
list-style-type
css
list-style
css
margin-block-start & margin-block-end
css
margin-inline-start & margin-inline-end
css
margin
css
mask-image
css
max-block-size
css
max-height property
css
max-width
css
min-height property
css
min-inline-size
css
min-width property
css
mix-blend-mode
css
lch(), oklch(), lab(), oklab()
css
object-fit
css
object-position
css
opacity
css
orphans
css
outline-offset
css
outline
css
overflow-wrap
css
overflow
css
padding-block-start & padding-block-end
css
padding-inline-start & padding-inline-end
css
padding
css
position
css
:active
css
:checked
css
:first-child
css
:first-of-type
css
:focus
css
:has()
css
:hover
css
lang()
css
:last-child
css
:last-of-type
css
:link
css
:not
css
:nth-child
css
:nth-last-child
css
:nth-last-of-type
css
:nth-of-type
css
:only-child
css
:only-of-type
css
:target
css
:visited
css
::after
css
::before
css
::first-letter
css
::first-line
css
::marker
css
::placeholder
css
radial-gradient()
css
rgb()
css
rgba()
css
scroll-snap
css
Adjacent sibling combinator
css
Attribute selector
css
Chaining selectors
css
Child combinator
css
Class selector
css
Descendant combinator
css
General sibling combinator
css
Grouping selectors
css
ID selector
css
Type selector
css
Universal selector *
css
shape-margin
css
shape-outside
css
system-ui, ui-serif, ui-sans-serif, ui-rounded, ui-monospace
css
tab-size
css
table-layout
css
text-align-last
css
text-align
css
text-decoration-color
css
text-decoration-line
css
text-decoration-style
css
text-decoration-thickness
css
text-decoration
css
text-emphasis-position
css
text-emphasis
css
text-indent
css
text-orientation
css
text-overflow
css
text-shadow
css
text-transform
css
text-underline-offset
css
text-underline-position
css
transform
css
CSS calc() function
css
ch unit
css
cm unit
css
em unit
css
ex unit
css
in unit
css
initial unit
css
mm unit
css
pc unit
css
% unit
css
pt unit
css
px unit
css
rem unit
css
vh unit
css
vmax unit
css
vmin unit
css
vw unit
css
CSS Variables (Custom Properties)
css
vertical-align
css
visibility
css
white-space
css
widows
css
width property
css
word-break
css
word-spacing
css
word-wrap
css
writing-mode
css
z-index
css
Not Supported
25 CSS features are not supported by Outlook.
Show 25 unsupported features
accent-color
css
aspect-ratio
css
border-inline & border-block individual logical properties
css
border-inline & border-block
css
border-radius logical properties
css
color-scheme CSS property
css
cursor
css
clamp()
css
light-dark()
css
hyphenate-character
css
hyphenate-limit-chars
css
inline-size
css
inset
css
margin-inline & margin-block
css
max-inline-size
css
min-block-size
css
CSS Nesting
css
padding-inline & padding-block
css
resize
css
text-decoration-skip-ink
css
text-justify
css
text-wrap
css
transition
css
user-select
css
white-space-collapse
css