body {
    font-family: system-ui;
} 
.zatemnenie {
background: rgba(102, 102, 102, 0.68);
width: 100%;
height: 100%;
position: fixed;
top: 0;
left: 0;
display: none;
z-index: 9999999999;
}

window {
position: absolute;
top: 50%;
left: 50%;
width: 400px;
border: 1px solid #cecece;
padding: 50px;
transform: translate(-50%,-50%);
background-color: #fafafa;
}

a.close_window {
	position: absolute;
    right: 10px;
    top: 4px;
    border: none;
    cursor: pointer;
    transition: 1s;
    color: #000000;
    font-size: 20px;
}

a.close_window:hover {
    color:rgb(152, 152, 152);
    transition: 1s;
}  
button{cursor: pointer;}