Mask in Chrome combining position absolute, overflow hidden, z-index and border-radius

Question

I am trying to achieve an effect, where I will have div with background image with content inside. This content should be flex-positioned div with the same image but blurred (while keeping its relative position to parent).

In search for salvation, I have discovered that certain combination of CSS rules make this exact effect, but only in Chrome.

.container {
  width: 320px;
  height: 240px;
  position: relative; /* it is required */
  display: flex; /* it is required */
  background: url(https://loremflickr.com/cache/resized/4848_46406748211_5572c760e0_320_240_nofilter.jpg);
}

.mask {
  z-index: 1; /* it is required */
  overflow: hidden; /* it is required */
  width: 150px;
  height: 150px;
  border-radius: 1px; /* it is required */
}

.element {
  background: url(https://loremflickr.com/cache/resized/4848_46406748211_5572c760e0_320_240_nofilter.jpg);
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  bottom: 0;
  filter: blur(5px);
}


<div class="container">
  <div class="mask">
    <div class="element"></div>
  </div>
</div>

https://jsfiddle.net/39um580g/16/

Chrome / Chrome Mobile:

Firefox:

Safari:

This is ridiculous. Is there a way I can make this solution cross-browser?

Answer to Moorthy G:

Let's suppose my block is placed on the right side. Current behavior of Chrome version is as I desire:

Adding any kind of transform will make .mask relative, so it will destroy desired effect:

Answer 1

Adding clip-path: polygon(0px 0px, 0px 100%, 100% 100%, 100% 0); clips your mask.

.mask {
  z-index: 1; /* it is required */
  overflow: hidden; /* it is required */
  width: 150px;
  height: 150px;
  border-radius: 1px; /* it is required */      
  clip-path: polygon(0px 0px, 0px 100%, 100% 100%, 100% 0); /* Fix for Firefox*/
}

Answer 2

One solution is to make the mask element position:absolute so that the overflow will work as expected then you consider adjusting the background-position while adjust the position of the element to rectify the image position.

I used CSS variable to make it easy to adjust:

 .container { width: 320px; height: 240px; position: relative; display: flex; --img:url(https://loremflickr.com/cache/resized/4848_46406748211_5572c760e0_320_240_nofilter.jpg); background:var(--img); } .mask { z-index: 1; overflow: hidden; width: 150px; height: 150px; top:var(--t,0); left:var(--l,0); position:absolute; border-radius: 50px; } .mask::before { content:""; display:block; background:var(--img) calc(-1*var(--l)) calc(-1*var(--t)); width:100%; height:100%; filter: blur(5px); } 

 <div class="container" style="--t:20px;--l:80px"> <div class="mask"> </div> </div> <div class="container" style="--t:90px;--l:0px"> <div class="mask"> </div> </div> <div class="container" style="--t:50px;--l:50px;--img:url(https://picsum.photos/320/240?image=1069)"> <div class="mask"> </div> </div>