Pain-free CSS3 with Sass and CSSPie

So, you have a great design for a site. Lots of rounded corners, soft shadows, and beautiful gradients. “This’ll be fun!”, you think.

Enter IE.

“Oh, crap”, you think.

Modern web design in IE is a pain in the rear. Fortunately, we have modern tools that make it a not-pain.

  • SASS (Syntactically Awesome Stylesheets) is a macro language for CSS. It lets you express CSS as nested rules, and gives you mix-ins, functionality extensions, variables, partials, and a whole lot more.
  • CSSPie is a set of behaviors for Internet Explorer that gives you CSS3 visual styles without really slow Javascript hacks like CurvyCorners.

When combined, the two are a shot of liquid awesome injected directly into your brain.

I’ve settled on a fairly standard setup for my projects. I have:

  • My application.sass file.
  • My _mixins.sass partial.
  • My behavior file.

Macros is very straightforward:

@mixin pie
  behavior: url(/behaviors/

@mixin shadows($color: #aaa, $x: 1px, $y: 2px, $spread: 2px)
  @extend .pie
  -moz-box-shadow: $color $x $y $spread
  -webkit-box-shadow: $color $x $y $spread
  box-shadow: $color $x $y $spread

@mixin inset-shadows($color: #aaa, $x: 1px, $y: 1px, $spread: 1px)
  @extend .pie
  -moz-box-shadow: inset $x $y $spread $color
  -webkit-box-shadow: inset $x $y $spread $color
  box-shadow: inset $x $y $spread $color

@mixin corners($tl: 5px, $tr: nil, $br: nil, $bl: nil)
  @extend .pie
  @if $tr == nil
    $tr: $tl
  @if $br == nil
    $br: $tl
  @if $bl == nil
    $bl: $tl
  -moz-border-radius: $tl $tr $br $bl
  -webkit-border-top-left-radius: $tl
  -webkit-border-bottom-left-radius: $bl
  -webkit-border-top-right-radius: $tr
  -webkit-border-bottom-right-radius: $br
  border-radius: $tl $tr $br $bl

@mixin vertical-gradient($start: #000, $end: #ccc)
  @extend .pie
  background: $end
  background: -webkit-gradient( linear, left top, left bottom, color-stop(0, $start), color-stop(1, $end) )
  background: -moz-linear-gradient(center top, $start 0%, $end 100%)
  -pie-background: linear-gradient(90deg, $start, $end)

What’s going on here? We’re defining several mix-ins for Sass:

+shadows([color, [x, [y, [spread]]]])
+inset-shadows([color, [x, [y, [spread]]]])
+corners(topleft, topright, bottomright, bottomleft)
+vertical-gradient(start, end)

Now, in your CSS, you can just do the following:

    family: Arial
    size: 10pt

  +vertical-gradient(#eee, #fff)

    color: #444

  +shadows(#888, 4px, 4px, 4px)
  +vertical-gradient(#444, #000)
  color: #fff
    color: #fff

.box, .dark-box
  padding: 1em
  margin-bottom: 1em

This expands to:

.pie, .box, .dark-box {
  behavior: url(/projects/;

body {
  font-family: Arial;
  font-size: 10pt;

.box {
  -moz-border-radius: 5px 5px 5px 5px;
  -webkit-border-top-left-radius: 5px;
  -webkit-border-bottom-left-radius: 5px;
  -webkit-border-top-right-radius: 5px;
  -webkit-border-bottom-right-radius: 5px;
  border-radius: 5px 5px 5px 5px;
  -moz-box-shadow: #cccccc 1px 2px 2px;
  -webkit-box-shadow: #cccccc 1px 2px 2px;
  box-shadow: #cccccc 1px 2px 2px;
  background: white;
  background: -webkit-gradient(linear, left top, left bottom, color-stop(0, #eeeeee), color-stop(1, white));
  background: -moz-linear-gradient(center top, #eeeeee 0%, white 100%);
  -pie-background: linear-gradient(270deg, #eeeeee, white);
.box h3 {
  color: #444444;

.dark-box {
  -moz-border-radius: 20px 20px 20px 20px;
  -webkit-border-top-left-radius: 20px;
  -webkit-border-bottom-left-radius: 20px;
  -webkit-border-top-right-radius: 20px;
  -webkit-border-bottom-right-radius: 20px;
  border-radius: 20px 20px 20px 20px;
  -moz-box-shadow: #888888 4px 4px 4px;
  -webkit-box-shadow: #888888 4px 4px 4px;
  box-shadow: #888888 4px 4px 4px;
  background: black;
  background: -webkit-gradient(linear, left top, left bottom, color-stop(0, #444444), color-stop(1, black));
  background: -moz-linear-gradient(center top, #444444 0%, black 100%);
  -pie-background: linear-gradient(270deg, #444444, black);
  color: white;
.dark-box h3 {
  color: white;

.box, .dark-box {
  padding: 1em;
  margin-bottom: 1em;

Check out the live demo.

Here are screenshots of the demo in Chrome 6, Firefox 4.0b3, Internet Explorer 8. Can you tell which browser is which?