Desktop

Postbox

A popular commercial email client for OS X/mac OS and Windows, which works with IMAP and POP3 accounts. It’s built on top of Thunderbird, and displays emails with its Gecko rendering.

Tested version 5.0.17 on macOS.

Selectors
E:visited
Media Queries
any-hover
any-pointer
hover
max-device-pixel-ratio
max-resolution

Partial. Supports dpi and dpcm values, but not dppx.

min-device-pixel-ratio
min-resolution

Partial. Supports dpi and dpcm values, but not dppx.

pointer
Text & Fonts
@font-face

Partial. User is prompted to download webfont, but only embedded (base64 encoded) fonts display.

EOT
SVG
TTF
WOFF
WOFF2
WOFF2 base64 encoded
font-feature-settings
font-kerning
font-stretch

Partial. Supports exact font-stretch matches, but doesn’t map non-matches to the nearest face.

font-synthesis
font-variant

Partial. Supports CSS2 values, but not CSS3.

hyphens
overflow-wrap
text-fill-color
text-overflow
text-size-adjust
text-stroke
text-stroke-color
text-stroke-width
Color & Background
background

Partial. Slash syntax values are not supported.

background-attachment
background-blend-mode
isolation
mix-blend-mode
Box Model
border-image
box-sizing
Positioning & Display
object-fit
object-position
overflow
position

Partial. Supports relative. Elements withfixed scroll with the page instead of remaining fixed. Buggy behavior for absolute positioning.

resize
Animations
animation
animation-delay
animation-direction
animation-duration
animation-fill-mode
animation-iteration-count
animation-name
animation-play-state
animation-timing-function
Transforms
backface-visibility
perspective
perspective-origin
transform
transform-origin
transform-style
Transitions
transition
transition-delay
transition-duration
transition-property
transition-timing-function
Filters
backdrop-filter
filter
Columns
break-after
break-before
break-inside
column-count
column-fill
column-gap
column-rule
column-rule-color
column-rule-style
column-rule-width
column-span
column-width
columns
Flexbox
align-content
align-items
align-self
display
flex
flex-basis
flex-direction
flex-flow
flex-grow
flex-shrink
flex-wrap
justify-content
order
Grid
align-content
align-items
align-self
display
grid
grid-area
grid-auto-columns
grid-auto-flow
grid-auto-rows
grid-column
grid-column-end
grid-column-gap
grid-column-start
grid-gap
grid-row
grid-row-end
grid-row-gap
grid-row-start
grid-template-areas
grid-template-columns
grid-template-rows
justify-content
justify-items
justify-self

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