styled panel mixin, based on the clever button

clever_panel.sass

// based on the original cleverButtons by Olivier Lacan & Andrew Smith (http://clevercode.net)
// I tweaked it work for simple panels
// modified by Adam Rensel

//edge can be: glow, stark, 3d, 3dLight
//border can be: solid, twoTone

=cleverPanel($radius : 5px, $textcolor : white, $from : #aaa, $to : #666, $edge : "3dLight", $border : "solid")

  // adjustable settings for padding
  padding: 0.3em .9em 0.3em
  
  // defaulting background to gradient end color
  background-color: $to
  +background-image(linear-gradient($from, $to))
  // legacy IE
  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#{$from}', endColorstr='#{$to}')
  -ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr='#{$from}', endColorstr='#{$to}')"
  
  @if $edge == "glow"
    +box-shadow(0 1px 1px rgba(0,0,0,.6), rgba(255,255,255,.9) 0px 1px 2px inset)

  @if $edge == "stark"
    +box-shadow(rgba(255,255,255,.7) 0 10px 10px inset, rgba(0,0,0,.4) 0 0 1px inset)

  @if $edge == "3d"
    +box-shadow(rgba(0,0,0,.9) 0 3px 1px, rgba(0,0,0,.4) 0 0 1px inset)
  
  @if $edge == "3dLight"
    +box-shadow(rgba(0,0,0,.5) 0 1px 1px, rgba(0,0,0,.4) 0 0 1px inset)
  
  // making sure IE gets at least a border
  @if $border == "twoTone"
    border-top: 1px solid lighten($from,30%)
    border-left: 1px solid lighten($from,30%)
    border-right: 1px solid saturate(darken($to, 10%), 10%)
    border-bottom: 1px solid saturate(darken($to, 10%), 10%)
  
  @if $border == "solid"
    border: 1px solid saturate(darken($to, 10%), 10%)
 	 
  // would benefit from CSS3 PIE radius
  +border-radius($radius)


  $is_light: lightness($textcolor) > 50%

  $dark_shadow_color : darken($textcolor,100%)
  $light_shadow_color : lighten($textcolor,100%)

  @if $is_light
    text-shadow: transparentize($dark_shadow_color, .4) 0 1px 0
  @if $is_light == false
    text-shadow: transparentize($light_shadow_color, .4) 0 1px 0
  &::-moz-focus-inner 
    border: 0
    padding: 0