PHP Variables in the CSS Stylesheet - php

Question

I am looking to introduce PHP variables to stylesheets (ie. CSS).
I have worked out that I can print a PHP page as a stylesheet by declaring:
header('Content-Type: text/css');
At the top of the CSS page.
However the variable I am passing is not displaying in the stylesheet.
In this case the PHP variable $css will be '-webkit-', '-moz-', '-ms-', or '-o-'.
And in the stylesheet I want to echo it in front of CSS3.
Originally I was achieving this by having a separate CSS file for each however this would be more efficient and allow me to pass genuine styling from the database, such as background-color and font.
Possible? How?
EXAMPLE PHP File called as a CSS link.
<?php
global $css;
header('Content-Type: text/css');
?>
.wheel {
position:absolute; top:50%; left:50%; height:32px; width:32px; margin:-16px; <?php echo $css;?>transition:opacity 0.3s;
}
.wheel li {
width:3px; height:9px; border-radius:2px; background:#555; <?php echo $css;?>animation:loading 1.2s infinite; position:absolute; <?php echo $css;?>transform-origin:2px 16px; left:16px; opacity:0; box-shadow:inset 0 0 2px rgba(255,255,255,0.4);
}
#<?php echo $css;?>keyframes loading { 0% {opacity:0.2;} 50% {opacity:0.9;} 100% {opacity:0.2;} }

Answer 1

If you just want to be able to use variables in your css (not necessarily php), you could consider using less

Answer 2

You do this the same way you would with HTML:
<?php
header('Content-Type: text/css');
$css = $_GET['css']; // or wherever your're initializing the variable from...
?>
body {
<?= $css ?>border-radius: 3px
}
But, I don't think this is necessary for your use case. It's actually not uncommon to just statically include all the various -*- options in a css file:
body {
-moz-border-radius: 3px;
border-radius: 3px;
}
Just add all effective options, and the browser will determine which are most effective for it. This also means you get to avoid the dull and error prone task of browser sniffing.

Answer 3

SASS CSS extension would allow you to use variables without actually needing to use PHP and the downsides that come with it. Mixins would simplify the generation of vendor-specific style rules.
#mixin vendor-prefix($name, $argument) {
-webkit-#{$name}: #{$argument};
-ms-#{$name}: #{$argument};
-moz-#{$name}: #{$argument};
-o-#{$name}: #{$argument};
#{$name}: #{$argument};
}
p {
#include vendor-prefix(hyphens, auto)
}