Issue with div with image as a gradient on high dpi devices - html

Question

I have the following HTML + CSS:
.item {
position: relative;
width: 400px;
height: 400px;
background: url('http://i.imgur.com/FOmRt87.jpg') no-repeat;
}
.item .gradient {
width: 100%;
height: 100%;
position: absolute;
bottom: 0;
left: 0;
background: url('http://i.imgur.com/oSpOTeK.png') repeat-x center bottom;
}
<div class="item">
<div class="gradient">
</div>
</div>
It's rendered in the browser properly. But on mobile (see the attached screenshot) there's a one thick line across the gradient, I have no idea why is that.
Here's also I js fiddle: https://jsfiddle.net/tcxka242/1/
First I thought that is repeated vertically as well, but the inspector says that the rule I've set: background: url(...) repeat-x center bottom; is expanded to :
background-image: url("http://i.imgur.com/oSpOTeK.png");
background-position-x: 50%;
background-position-y: 100%;
background-size: initial;
background-repeat-x: repeat;
background-repeat-y: no-repeat;
background-attachment: initial;
background-origin: initial;
background-clip: initial;
background-color: initial;
That's on Android Phone with Google Chrome.

Answer 1

Sorry but i cannot properly verify this , but i have an idea for you .
.item .gradient {
width:100%;
height: 100%;
position: absolute;
bottom: 0;
left: 0;
outline: 0;
border: none;
background: url('http://i.imgur.com/oSpOTeK.png') repeat-x center bottom;
}
As you can see i have set the outline to 0 and the border to none . There's a possibility that there is an outline from the div or a hidden border .

Answer 2

Specifying border-top: 0px; and box-shadow: none; will work for you
.item .gradient {
width: 100%;
height: 100%;
position: absolute;
bottom: 0;
box-shadow: none;
left: 0;
background: url('http://i.imgur.com/oSpOTeK.png') repeat-x center bottom;
border-top: 0px;
}

Answer 3

I think this is caused on screens with high DPI. Therefore I am providing a CSS-only alternative.
https://jsfiddle.net/tcxka242/6/
.item {
position: relative;
width: 400px;
height: 400px;
background: url('http://i.imgur.com/FOmRt87.jpg') no-repeat;
}
.item:after {
content: "";
width: 100%;
height: 100%;
position: absolute;
bottom: 0;
left: 0;
z-index: 1;
pointer-events: none;
background: linear-gradient(to bottom, rgba(0, 0, 0, 0) 0%, rgba(0, 0, 0, 0) 70%, rgba(0, 0, 0, 0.6) 100%);
}