smoothing animation

Hi
It could be nice to modify the css file : 
```
div.instrument .box {
	position: absolute;
	top: 0;
	left: 0;
	width: 100%;
	height: 100%;
}
```
to : 
```
div.instrument .box {
	position: absolute;
	top: 0;
	left: 0;
	width: 100%;
	height: 100%;
	transition: transform .3s;
}
```
cheers