How to remove black bar when scrolling page in safari?

Question

css

How to remove black bar when scrolling on iphone?
There is a fixed image in the background. When the panel is hidden from below, then the height of the picture is not enough at first and a black bar is formed.
This is how it looks on iphone

Here is the code of the block with the picture
<div class="img-bg"></div>

.img-bg {
  position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    width: 100vw;
    height: 100vh;
    background: url(/images/bg.png) no-repeat;
    background-position: center top;
    background-clip: border-box;
    opacity: 0.15;
    z-index: 5;
    transition: opacity 400ms cubic-bezier(0.39, 0.575, 0.565, 1);
    -webkit-transition: opacity 400ms cubic-bezier(0.39, 0.575, 0.565, 1);
    -moz-transition: opacity 400ms cubic-bezier(0.39, 0.575, 0.565, 1);
}

Answer 1

Try giving the element a negative bottom margin, or a transparent bottom border:
border-bottom: 1px transparent solid;