body {
  background: linear-gradient(120deg, #888, #444);
  color: black;
  font-family: Verdana;
}

.one {
  align-items: center;
  text-align: center;
  justify-content: center;
  margin-top: 10%;
  position: relative;
  width: 300px;
  height: 300px;
  border-radius: 7px;
  border: 2px solid black;
  overflow: hidden;
}

.one::before {
  content: "";
  position: absolute;
  inset: 0;
  background: rgba(255, 255, 255, 0.4);
  filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 0;
}


.one > * {
  position: relative;
  z-index: 1;
}