<div class="flex__container">
  <div class="flex__item">:)</div>
</div>

@import url("https://fonts.googleapis.com/css?family=Gochi+Hand");

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  width: 100vw;
  min-height: 100vh;
  margin: 0;
  background-color: #291642;
  font-family: "Gochi Hand", sans-serif;
  font-size: 100%;
  letter-spacing: 0.1rem;
  color: #fff;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;

  background: linear-gradient(to right, #44ea76 0%, #39fad7 80%, #39fad7 100%)
      no-repeat,
    url("https://lh4.googleusercontent.com/-3eBjuQpOGFw/U47yh_-OycI/AAAAAAAAI2U/uaU5pK49N1w/s1600/normal.jpg")
      no-repeat fixed;
  background-size: cover;
  background-blend-mode: hue;
}

.flex__container {
  inline-size: 50vw;
  block-size: 50vh;

  display: flex;
  justify-content: center;
  align-items: center;

  border-radius: 5px;
  box-shadow: 0 20px 30px rgba(0, 0, 0, 0.6);
  border: 1px solid rgba(255, 255, 255, 0.3);
  padding: 4vh;
  text-shadow: 0 1px 1px rgba(0, 0, 0, 0.4);
  transition: box-shadow 0.3s ease;

  overflow: hidden;
  resize: both;

  background-image: linear-gradient(
    0deg,
    rgba(255, 255, 255, 0.5),
    rgba(255, 255, 255, 0.5)
  );
  backdrop-filter: blur(3px);
}

.flex__item {
  font-size: 3rem;
  padding: 4vh;
  background: #7b44bc;
  border-radius: 4px;
}