Writing CSS as Writing Program

编写 CSS 时要是可以『变量替换』和『层次嵌套』可以避免很多重复的部分。

SASS / SCSS

• https://sass-lang.com

$font-stack:    Helvetica, sans-serif;
$primary-color: #333;

body {
  font: 100% $font-stack;
  color: $primary-color;
}

LESS

• http://lesscss.org

It's CSS, with just a little more.

@width: 10px;
@height: @width + 10px;

#header {
  width: @width;
  height: @height;
}