iOS safari设置平滑滚动后，fixed定位错误

Safari 设置平滑滚动
```css
body {
-webkit-overflow-scrolling:touch;
}
```

如果页面有``position: fixed``的元素，那么页面布局会错乱

则需要设置transform

```css
.element {
position: fixed;
transform: translateZ(0);
-webkit-transform: translateZ(0);
}
```

相关问题

https://stackoverflow.com/questions/22167382/position-fixed-not-working-on-windows-safari