I want to move place my dashed line **behind** my divs.
It keep staying on the top of my divs.

Here what I currently have right now : 

![enter image description here](https://i.stack.imgur.com/fmfuh.png)

Here what I am hoping to get : 

![enter image description here](https://i.stack.imgur.com/8h18H.png)

```
**CSS** 

/*Background Border*/
.border-center {
  width: 100%;
  position: relative;
}

.slide:before {
  content: '';
  position: absolute;
  border-bottom: 3px #3498db dashed;
  z-index: 1;
  top: 50%;
  margin-top:-2px;
  right: 10%;
  left: 40%;
  width: 25%; 

}

```

I wish I can put more code, since my rep is low, I got this warning : 

![enter image description here](https://i.stack.imgur.com/Vi4us.png)

More details : [`JSFiddle`](http://jsfiddle.net/bheng/1q6ur85k/)