Modified to work better with express/connect compiler.

Changes

• All mixins are now functions to prevent unused mixins from polluting compiled scripts.
• Use line comments vs block comments.
• Added box-sizing mixin
• Added user-select mixin

Mixins

Box Sizing:

/* LESS */

h1 {
  .box-sizing;
}

h2 {
  .box-sizing(content-box);
}

/* Compiled CSS */

h1 {
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
  box-sizing: border-box; 
}

h2 {
  -moz-box-sizing: content-box;
  -webkit-box-sizing: content-box;
  box-sizing: content-box; 
}

User Select:

/* LESS */

h1 {
  .user-select;
}

h2 {
  .user-select(text);
}

/* Compiled CSS */

h1 {
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -o-user-select: none;
  user-select: none;
}

h2 {
  -webkit-user-select: text;
  -khtml-user-select: text;
  -moz-user-select: text;
  -o-user-select: text;
  user-select: text;
}