We are attempting to use background: linear-gradient() to get the following output. However, we are running into a problem where the css is not being applied to the following browsers. 
Question:
How can we get it to work on all browsers?
Browsers with issues
- Mac High Sierra Safari 11.1
 - IE11
 - Microsoft Edge 44.17763.771.0
 - Safari on iOS (v12)
 
What we tried
.box { 
  padding:20px;
  display:inline-block;
  border-right:2px solid #000;
  border-left:2px solid #000;
  background:
    linear-gradient(to left ,#000 10px,transparent 10px 30px,#000 0) top,
    linear-gradient(to right,#000 10px,transparent 10px 30px,#000 0) bottom;
  background-size:100% 2px;
  background-repeat:no-repeat;
}
<div class="box">
Some text inside
</div>