How to inherit a certain position (CSS) - html

Question

After ~2 hours of researching I couldn't find a solution for my problem, I am trying to inherit the center of the background since the "blurred-box" gets bigger depending on the computer resolution.
It looks like this(laptop resolution):
And I would like to make it show the center of the background image instead of the corner.
* {
margin: 0;
padding: 0;
}
html {
width: 100vw;
height: 100vh;
}
body {
background-repeat: no-repeat;
background-attachment: fixed;
background-size: cover;
background-position: top;
background-image: url(https://images.unsplash.com/photo-1477346611705-65d1883cee1e?dpr=0.800000011920929&auto=format&fit=crop&w=1199&h=800&q=80&cs=tinysrgb&crop=);
width: 100%;
height: 100%;
font-family: Arial, Helvetica;
letter-spacing: 0.02em;
font-weight: 400;
-webkit-font-smoothing: antialiased;
}
.blurred-box {
position: fixed;
width: 550px;
height: 670px;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
background: inherit;
border-radius: 2px;
overflow: hidden;
}
.blurred-box:after {
content: '';
width: 1000px;
height: 1000px;
background: inherit;
position: absolute;
bottom: 0;
box-shadow: inset 0 0 0 200px rgba(255, 255, 255, 0.05);
filter: blur(10px);
}
.user-login-box {
position: relative;
margin-top: 50px;
text-align: center;
z-index: 1;
}
.user-login-box>* {
display: inline-block;
}
<div class="blurred-box">
<div class="user-login-box">
<h1>text here</h1>
</div>
</div>
If someone posts a solution I would like to have a link for documentation with those informations(if that is okay), thanks.

Answer 1

You are almost good, remove the use of translate() which is creating the issue and center your element using margin:auto instead:
body {
background-repeat: no-repeat;
background-attachment: fixed;
background-size: cover;
background-position: top;
background-image: url(https://images.unsplash.com/photo-1477346611705-65d1883cee1e?dpr=0.800000011920929&auto=format&fit=crop&w=1199&h=800&q=80&cs=tinysrgb&crop=);
margin:0;
height: 100vh;
font-family: Arial, Helvetica;
letter-spacing: 0.02em;
font-weight: 400;
-webkit-font-smoothing: antialiased;
}
.blurred-box {
position: fixed;
width: 550px;
height: 670px;
top: 0;
left: 0;
bottom:0;
right:0;
margin:auto;
background: inherit;
border-radius: 2px;
overflow: hidden;
}
.blurred-box:after {
content: '';
width: 1000px;
height: 1000px;
background: inherit;
position: absolute;
bottom: 0;
box-shadow: inset 0 0 0 200px rgba(255, 255, 255, 0.05);
filter: blur(10px);
}
.user-login-box {
position: relative;
margin-top: 50px;
text-align: center;
z-index: 1;
}
.user-login-box>* {
display: inline-block;
}
<div class="blurred-box">
<div class="user-login-box">
<h1>text here</h1>
</div>
</div>