define( [
  	"../core",
  	"../var/rcssNum"
  ], function( jQuery, rcssNum ) {
  
  "use strict";
  
  function adjustCSS( elem, prop, valueParts, tween ) {
  	var adjusted,
  		scale = 1,
  		maxIterations = 20,
  		currentValue = tween ?
  			function() {
  				return tween.cur();
  			} :
  			function() {
  				return jQuery.css( elem, prop, "" );
  			},
  		initial = currentValue(),
  		unit = valueParts && valueParts[ 3 ] || ( jQuery.cssNumber[ prop ] ? "" : "px" ),
  
  		// Starting value computation is required for potential unit mismatches
  		initialInUnit = ( jQuery.cssNumber[ prop ] || unit !== "px" && +initial ) &&
  			rcssNum.exec( jQuery.css( elem, prop ) );
  
  	if ( initialInUnit && initialInUnit[ 3 ] !== unit ) {
  
  		// Trust units reported by jQuery.css
  		unit = unit || initialInUnit[ 3 ];
  
  		// Make sure we update the tween properties later on
  		valueParts = valueParts || [];
  
  		// Iteratively approximate from a nonzero starting point
  		initialInUnit = +initial || 1;
  
  		do {
  
  			// If previous iteration zeroed out, double until we get *something*.
  			// Use string for doubling so we don't accidentally see scale as unchanged below
  			scale = scale || ".5";
  
  			// Adjust and apply
  			initialInUnit = initialInUnit / scale;
  			jQuery.style( elem, prop, initialInUnit + unit );
  
  		// Update scale, tolerating zero or NaN from tween.cur()
  		// Break the loop if scale is unchanged or perfect, or if we've just had enough.
  		} while (
  			scale !== ( scale = currentValue() / initial ) && scale !== 1 && --maxIterations
  		);
  	}
  
  	if ( valueParts ) {
  		initialInUnit = +initialInUnit || +initial || 0;
  
  		// Apply relative offset (+=/-=) if specified
  		adjusted = valueParts[ 1 ] ?
  			initialInUnit + ( valueParts[ 1 ] + 1 ) * valueParts[ 2 ] :
  			+valueParts[ 2 ];
  		if ( tween ) {
  			tween.unit = unit;
  			tween.start = initialInUnit;
  			tween.end = adjusted;
  		}
  	}
  	return adjusted;
  }
  
  return adjustCSS;
  } );