main {
    width: 600px;
    height: 400px;
    position: relative;
    background: #eee;
}
.overlay {
    position: absolute;
    inset: 0;
    background: red;
    backdrop-filter: 2em;
    display: flex;
    justify-content: center;
    align-items: center;
}
#check {
    position: absolute;
    display: none;
    z-index: 3;
}
#check:checked + .overlay {
    display: none;
}
label {
    border :1px solid;
    padding: 1em 2em;
}